Forensic 6 Lec
Forensic 6 Lec
Forensic 6 Lec
INTRODUCTION
Ballistics (gr.ba'llein, "throw") is the science that deals with the motion, behavior, and effects of projectiles, especially
bullets, gravity bombs, rockets, or the like, and the condition that affect its motion; the science or art of designing and hurling
projectiles so as to achieve a desired performance. A ballistic body is a body which is free to move, behave, and be modified in
appearance, contour, or texture by ambient conditions, substances, or forces, as by the pressure of gases in a gun, by rifling in a
barrel, by gravity, by temperature, or by air particles.
Motion refers to the mobility or movement of the projectile from the time it leaves the empty shell; it leaves the gun
muzzle until it reaches its target or falls on the ground.
1) Direct motion – the forward motion of the bullet or shots out of the shell by the action of the expansive force of
gases from a burning gunpowder
2) Rotatory motion – is the action of the bullet passing through a rifled bore barrel firearm which is either twisted to
the left or to the right
3) Translational motion – is the action of the bullet once it hits an object or the target and subsequently ricocheted.
Firearm ballistics information is used in forensic science. Separately from ballistics information, firearm and tool mark
examinations involve analyzing firearm, ammunition, and tool mark evidence in order to establish whether a certain firearm or
tool was used in the commission of a crime.
1. Internal ballistics, the study of the processes originally accelerating the projectile, for example the passage of a bullet
through the barrel of a rifle;
2. External ballistics, the study of the passage of the projectile through space or the air; and
3. Terminal ballistics, the study of the interaction of a projectile with its target, whether that be flesh (for a hunting bullet),
steel (for an anti-tank round), or even furnace slag (for an industrial slag disruptor).
“Ballista” is a gigantic bow or catapult which was used to hurl large objects such as stones at a particular distance to
deter animals or enemy forces.
Today, the word Ballistics is frequently used synonymously in the press and in the Police Parlance to Firearms
Identification.
BALLISTICS
It is a science in itself because it evolved from systematic knowledge, research and development, training, experience
and education of those who pioneered in this field.
Technically speaking, it refers to the "science of firearms identification which involves the scientific examination of
ballistics exhibits such as: fired bullets; fired shells; firearms; and allied matters, used in crime.
Legally speaking, ballistics is the microscopic examination of fired cartridge cases and bullets together with the
recording and presentation by means of photography of what is revealed by the microscope.
BALLISTICS THEORY
Ballistics is the scientific study of the propulsion and motion of projectiles such as bullets, artillery shells, rockets
and guided missiles. Also includes the study of the destructive action of such projectiles.
The drag of a projectile moving head on is now usually divided into three parts:
1. GALILEO,NEWTON, and LEIBNIZ established the principles of dynamics and the methods of calculus, studies
which helped the rapid development of external ballistics.
2. GALILEO and NEWTON were both interested in the force called air resistance, now usually called aerodynamic
drag, which reduces the speed of a projectile.
3. In 1707, CASSINI, an astronomer suggested measuring firearm’s muzzle velocity.
Interior ballistics deals with the temperature, volume, and pressure of the gases resulting from combustion of the
propellant charge in the gun; it also deals with the work performed by the expansion of these gases on the gun, its carriage, and
the projectile. Some of the critical elements involved in the study of interior ballistics are the relationship of the weight of charge
to the weight of projectile; the length of bore; the optimum size, shape, and density of the propellant grains for different guns; and
the related problems of maximum and minimum muzzle pressures.
The British engineer Benjamin Robins conducted many experiments in interior ballistics. His findings justly entitle him
to be called the father of modern gunnery.
Late in the 18th century the Anglo-American physicist Benjamin Thompson made the first attempt to measure the
pressure generated by gunpowder. The account of his experiments was the most important contribution to interior ballistics that
had been made up to that time.
About 1760 French ballisticians determined the relationship of muzzle velocity to length of barrel by measuring the
velocity of a musket ball and cutting off a portion of the barrel before taking the velocity of the next shot. By using the results of
these experiments and advances in chemistry and thermodynamics, ballisticians developed formulas showing the relationship
between muzzle velocity and weight and shape of projectile; weight, type, and grain size of powder charge; pressure and
temperature in the barrel; and the size of the powder chamber and the length of the barrel.
Exterior Ballistics deals with the motion of projectiles from the time they leave the muzzle of the firearm to the time they
hit the target. The flight of most bullet or projectile does not exceed 30 seconds at maximum range, which for almost any firearms
is obtained at an elevation of about 33.
In exterior ballistics, elements such as shape, caliber, weight, initial velocities, rotation, air resistance, and gravity help
determine the path of a projectile from the time it leaves the gun until it reaches the target.
Until the middle of the 16th century it was believed that bullets move in straight lines from the gun to the target and that
shells fired from mortars describe a path made up of two straight lines joined by an arc of a circle. The Italian mathematician
NiccolòTartaglia, in a published work on gunnery, claimed that no part of the path of a projectile could be a straight line and that
the greater the velocity of the projectile the flatter its path. Tartaglia invented the gunner's quadrant used to determine elevation
of the muzzle of a gun. He is and Italian scientist who a book in which he said that the trajectory of a bullet was really a
continuous curve. He directed some firing tests to determine this angle, and discovered that it was near 45 degrees and he noted
that the trajectory was continuously curve.
Galileo proved that in a vacuum a projectile describes a parabolic arc. The description of the law of gravitation by the
British scientist Sir Isaac Newton made plain the cause of the curvilinear motion of projectiles. By the use of calculus he
determined the momentum transferred from the projectile to the particles of air at rest; this method of calculating air drag has
been superseded by the use of tables prepared from experimental firings.
Two methods have been used to determine the velocity of a projectile after it leaves the gun. One method measures
the momentum of the projectile; the other measures the time required for the projectile to travel a given distance. The first
method is the older, and in the past, when guns and projectiles were small, velocities low, and ranges short, the results were
sufficiently accurate for most practical purposes. The ballistic pendulum and gun pendulum were used to measure projectile
momentum, but these devices have been supplanted by cheaper and more accurate machines working on the principles of the
second method.
The ballistic pendulum was developed about 1743 by Robins, who was the first to undertake a systematic series of
experiments to determine the velocity of projectiles. The principle of the ballistic pendulum, as well as of the gun pendulum,
which was developed by Thompson, is the transfer of momentum from a projectile with a small mass and a high velocity to a
large mass with a resultant low velocity.
The ballistic pendulum consisted of a massive plate of iron to which was bolted a block of wood to receive the impact
of the projectile; the pendulum was suspended freely from a horizontal axis. The block, when struck by the projectile, recoiled
through a certain arc that was easily measured. Knowing the arc of recoil and the masses of the projectile and the pendulum, the
velocity of the projectile could be determined by calculation. The ballistic pendulum was able to withstand the impact of musket
balls only; however, by determining the relations that should exist between the caliber, length of barrel, and charge of power,
Robins substantially advanced the science of gunnery.
By the second method, the velocity of a projectile is determined by measuring the time required for it to travel a known
length of its path. Numerous machines have been devised for this purpose; in 1840 the British physicist Sir Charles Wheatstone
suggested the use of electricity for measuring small intervals of time. This suggestion led to the development of the chronograph,
a device for recording, by electrical means, the time required for a projectile to pass between two screens of fine wire.
The formulas and tables for the exterior ballistics of each new type of gun or cannon are more or less empirical and
must be tested by actual experiment before the aiming devices can be accurately calibrated.
Further, exterior (external) ballistics refers to the attributes and movements of the bullet after it has left the gun
muzzle. It includes:
1. Muzzle blast - the noise created at the muzzle point of the gun due to the sudden escape of the expanding gas
coming in contact with the air in the surrounding atmosphere at the muzzle point.
2. Muzzle energy - energy generated at the muzzle point.
3. Trajectory - the actual curved path of the bullet during its flight from the gun muzzle to the target. The following
are the kinds of trajectory: straight horizontal line - parabola-like flight - vertical drop
4. Range - the straight distance between the muzzle point and the target.
a. Accurate (effective) range - the distance within the shooter has control of his shots, meaning he can place
his shots at the desired spots.
b. Maximum range - the farthest distance that a projectile can be propelled from a firearm.
* While the range at which the ordinary pistol and revolver are supposed to be effective in only 50-70 yards,
all of them can send their bullets much further than that and are capable of inflicting fatal wounds at distances up to
one mile, depending on the caliber and gunpowder content.
Long barrel rifle – up to 3,000 yards accurate range and its hinge muzzle velocity of 1000-4000 ft./sec.
* Bullets from rifled weapons spin at 2000-3000 revolutions per second, but over the first few yards of
trajectory – distance varies with the weapon – their flight is slightly unstable; the end of the projectile wobbles before it
picks up a smooth flight path. This phenomenon is called “TAILWAG”, and is of considerable important in evaluating
gunshot wounds. A bullet with “tailwag” does not strike its target clearly.
1. Accuracy Range – The maximum distance at which a particular gun and cartridges will consistently place all shots in
the standard target for that distance.
2. Accurate Range – The distance within which the shooter has control of his shots.
3. Back Curve - This is that portion of the bullets trajectory that drops below the critical zone beyond the point blank
range. Past this point the trajectory begins to drop off very rapidly with range and the point of impact becomes very
difficult to estimate.
4. Ballistic Coefficient – The means that the bullet may lose its speed very rapidly during its flight the air. This is a number
that relates to the effect of air drag on the bullet's flight and which can be used to later predict a bullet's trajectory under
different circumstances through what are called "drag tables."
5. Bullet Energy – the power possessed by a moving bullet, or in other words, its ability to keep going when it meets an
obstacle and to do work on the obstacle is immense importance, for obviously the more power a bullet has an the
harder it is to stop the more effective it can be as a weapon
6. Bullet Trajectory - This is the bullet's path as it travels down range. It is parabolic in shape and because the line of the
bore is below the line of sight at the muzzle and angled upward, the bullet's path crosses the line of sight at two
locations.
7. Critical Zone - This is the area of the bullet's path where it neither rises nor falls greater than the dimension specified.
Most shooters set this as ± 3" to 4" from the line of sight, although other dimensions are sometimes used. The
measurement is usually based on one-half of the vital zone of the usual target. Typical vital zones diameters are often
given as: 3" to 4" for small game, and 6" to 8" for big game and anti-personnel use.
8. Drift - is the curve taken by the bullet while in flight. A right hand rifling curves to the right while that of the left and rifling
curves to the left.
9. Effective Range- The maximum distance at which a bullet may reasonably be expected to travel accurately and kill a
particular type of live target.
10. Extreme Range – The greatest distance the bullet will travel when the cartridge is fired.
11. Flat Trajectory - A comparative term used to indicate very little curvature in the flight in the bullet from muzzle to point
of impact. When the velocity is high, comparatively flat trajectory.
12. Gallery Range - The indoor target range. National rifle association of America, gallery rules required stance from firing
point to target of 50 feet or 75 feet for.22 rim fire riffle; 50 feet or 60 feet for .22rim-fire pistols. On properly constructed
indoor ranges, firing may be conducted with center fire pistol and revolvers at ranges of 25 yards and 50 yards. Such
installation are generally referred to as “indoor range” the term “gallery” being applied usually only to the short
range .22 caliber installation.
13. Gallery Range - The indoor target range. National rifle association of America, gallery rules required stance from firing
point to target of 50 feet or 75 feet for.22 rim fire riffle; 50 feet or 60 feet for .22rim-fire pistols. On properly constructed
indoor ranges, firing may be conducted with center fire pistol and revolvers at ranges of 25 yards and 50 yards. Such
installation are generally referred to as “indoor range” the term “gallery” being applied usually only to the short
range .22 caliber installation.
14. Initial Point - The range at which the bullet's trajectory first crosses the line of sight. This is normally occurs at a range
of about 25 yards.
15. Instrument Velocity - the velocity of a projectile measured by the scientific instrument called chronograph, at a specified
point on its trajectory. Always lower than the muzzle velocity.
16. Key-hole Shot – the tumbling of the bullet in its flight and hitting the target sideways as a result of not spinning on its
axis.
17. Maximum Point Blank Range - This is the farthest distance at which the bullet's path stays within the critical zone. In
other words the maximum range at which you don't have to adjust your point of aim to hit the target's vital zone. Unless
there is some overriding reason to the contrary shots should not generally be attempted much past this distance. In the
words of the Guru, "It is unethical to attempt to take game beyond 300 meters." If you do, you should write yourself a
letter explaining why it was necessary to do so. An approximate rule of thumb says that the maximum point blank
range is approximately your zero range plus 40 yards.
18. Maximum Range – the farthest distance that a projectile can be propelled from a firearm.
19. Maximum Ordinate - This is the maximum height of the projectile's path above the line of sight for a given point of
impact and occurs somewhat past the halfway point to the zero range and it is determined by your zeroing range.
20. Mid-range Trajectory - This is the height of the bullets path above the line of sight at half way to the zero range. It does
not occur at the same range as the maximum ordinate height which can be greater.
21. Minute of Angle (MOA) - A "minute" of angle is 1/60 of a degree which for all practical purposes equates to 1 inch per
100 yards of range. Thus 1 MOA at 100 yards is 1 inch and at 300 yards it is 3 inches. The term is commonly used to
express the accuracy potential of a firearm.
22. Point Blank Range – Popularly used to indicate the distance the bullet will travel before it drops enough to require sight
adjustment. A short fired so closed to the target that no sighting is necessary for effective aiming.
23. Ricochet – The bouncing off or deflection of a bullet from its original trajectory (normal path) after striking a resistant
surface.
24. Shocking Power – the power of the bullet that results in the instantaneous death of the victim.
25. Stopping Power – the power of the bullet that put the victim out of action instantly. So it should be understood that
stopping power is not necessarily the same thing as killing power. However, stopping power depends very largely on
the location of the sot.
26. Target – an object at which the firearm is aimed and discharged.
27. True Drop – the actual distance the bullet falls during the time of flight to the target. This is not the same as what we
speak of when we discuss drop in the ordinary sense, which is more properly termed effective or apparent drop
28. Zero Range - This is the farthest distance at which the line of sight and the bullet's path intersect.
TERMINAL BALLISTICS
It is the study dealing with the effect of the impact of the bullet on the target. Penetration of the bullet is of prime
interest. Penetration is important also in determining safety requirements for target backstops. They are important to both
sportsman and military.
Terminal ballistics also deals with the destructive actions and effects that occur at the end of the projectile's flight
as an integral and un-deformed body. The flight may end in one of two ways:
SHOTS BALLISTICS - deals with the attributes and properties of shots and pellets.
CHOKE - When the diameter of a barrel of a shotgun is the same throughout the bore, it is called true cylinder.
The bore of the gun is sometimes constricted near the muzzle end. That is, the diameter near the muzzle end is
slightly smaller than the diameter of the bore of the rest of the barrel. The barrel is said to be choked.
Full – if reduced by one mm; half if reduced by one-half mm; quarter if reduced by ¼ mm; and improved cylinder if
reduced by about 1/10 mm.
The amount of spread in the shot is controlled by the choke. If a barrel will put 70 percent of its shot charge in a 30-
inch (76-centimeter) circle at 40 yards (37 meters), it is called full choke. Modified choke will deliver about 60 percent; improved
cylinder about 50 percent. A full choke 12-gauge gun will kill ducks that are about 60 to 65 yards (55 to 59 meters) away.
Chilled Shot – shotgun pellets made from lead especially hardened by the addition of a slight amt. of antimony.
Gunshot Wound (GSW). It is an open wound produced by the penetration of bullet slug within the tissues of the
body. The bullet which was propelled from the gun as well as the flame from the heated expanded gases in short range fire
is the one that produces injury.
1. Muzzle Pattern – indicates contact wound and are often observed in suicide cases. The whole charge (projectile,
wads, if any, smoke, unburnt or semi-burnt powder particles and hot gases) enter into the target. No burning,
blackening and tattooing are observed. Instead, they are observed inside the hole through careful examination.
The edges are found ragged (torn in star shape) and the wound is like an exit wound.
2. Scorching – caused by the flame or hot gases not by the hot projectiles as is commonly believed. It is also
known as burning or charring.
3. Blackening – caused by the deposition of smoke particles by all types of powders at close ranges. Being light
particles, they soon lose their velocity and get deposited on any material available in the path.
4. Tattooing (a.k.a. peppering) – caused by the embedding of unburnt and semi-burnt powder particles into the
surface of the target. These particles are slightly heavier than the smoke particles. They retain motion to
somewhat longer intervals and consequently cause tattooing to a distance of about one and a-half times
blackening range.
1. Pink Coloration – caused by absorbed carbon monoxide in the skin and flesh.
2. Dirt Ring – deposited by some projectile (which carry greases on them) around the wound. Existence of this
indicates the entrance side of a firearm injury & does not indicate range.
3. Contusion – caused by the impact of the projectile (reddish dark to bluish black - varies somewhat with the age of
the injury). It takes the form of a belt around the wound. It is of uniform in thickness.
4. Foreign Materials – Their presence not only permits the identification of the firearms injury but they also permit a
fairly reliable guess of firearm.
1. Kind of weapon - The higher power the weapon is the more destructive to the tissues of the body.
2. Caliber of the weapon - The higher the caliber of the wounding bullet, the greater will be the size of the wound of
entrance, hence, greater destruction to the tissues.
3. Shape and composition of the missile - The conical shape free end of the bullet slug has more penetrating power
but less tissue destruction, while bullet slug with hemispherical free end had less penetrating but more
destruction to the tissues.
* Some bullets were made to be deformed upon heating the target like the hallow point, dum-
dum and soft point bullet. Bullets made of hard metals like the magnum 44 and the armor-piercing bullet are
not usually deformed upon hitting the target. Other bullets and the fragments may cause further injury to the
body. The tracer bullet is in flame during its flight to the air and may caused burn upon hitting the body and this
bullet is also used in targeting the low flying airplane.
4. Range of fire - the injury is not only due to the missile but also due to the pressure of the heated expanded
gases, flame and articles of gunpowder. However, in long range fire, the characteristic effect of the bullet alone
will produce the injury.
5. Direction of fire - A right angle approach of the bullet to the body will produce a round shape wound of entrance in
short distance fire, while in acute angle of approach the bullet will produce an oval shape wound of entrance with
contusion collar widest on the side of the acute angle of approach and a tendency for the bullet to deflect to
another direction upon hitting the target.
6. Part of the body involved - When the bullet hit the soft tissues of the body; the bullet penetrates and
usually without any change in direction, however upon hitting the bones and other hard body structures the bullet
may fracture the bones causing further injury or may deflect to another direction.
Description of the wound of entrance is based on the distance of the body from the fired gun
1. Contact fire. Thisis burst due to the explosion of the powder which produces the heated and expanded gases.
There is burning of the tissues because it is within the flame zone; singeing of the hair; and particles of
gunpowder in and around the wound of entrance; skin is separated from the underlying tissues in the affected
area and the blasted tissues are cherry red in color because of the presence of carbon monoxide; pressure of the
bullet will caused caving-in or excavation of tissues and the contusion collar is seen around the wound of
entrance. The size of the wound is rather small.
2. Near contact up to six inches distance. There is bursting of tissues, burning and blackening of the skin as in
contact fire but the particles of gunpowder are present inside as well as around the wound of entrance. The
shape of the wound maybe lacerated or slit-like and the size is larger than the diameter of the missile. The
excavation of tissues due to the pressure of the penetrating bullet slug but it can be severe as in contact fire.
3. Distance above six inches up to 24 inches. The size of the wound gradually approximates the size of the missile.
The farther the target, the lesser the burning or blackening of tissues, gun powder tattooing, singeing of the hair
and excavation of tissues and lesser until they disappear beyond the 24 inches distance.
1. Size of the wound smaller than the missile bigger than the missile Averted
2. Edge of the wound Inverted no definite shape
3. Shape of the wound Round or oval absent
4. Contusion collar present in contact absent
5. Gunpowder tattooing and near contact fire maybe absent if the slug is
6. Presence or absence always present lodged inside the body
7. Protrusion of tissue Absent maybe present
8. Paraffin test + in contact and near fire negative
Shotgun Wound - It is an open wound produced by the penetration of pellets or shots within the tissues of the
body. In shotgun fire, the pellets penetrate and usually lodged inside the body and a tendency for a wider dispersion of
pellets at a certain distance except in contact and near contact fires.
1. Contact fire - irregular with bursting of the affected tissues due to explosion of the heated and expanded with
accompanying flame causing burning of the skin and the tissues. There is singeing of the hair; presence of wads
and particles of gunpowder inside the wound of entrance.
2. Near shot up to six inches distance. There is marked laceration of the skin and destruction of tissues due to the
pressure of explosion. The burning on the surface of the skin and particles of gunpowder are present inside and
around the wound of entrance. There is singeing of the hair as well as pieces of wads inside and outside the
wound of entrance.
3. Distance about one yard. The pellets penetrate the tissues as one mass making the wound with irregular edge of
the wound of entrance. There will also be blackening of tissues with slight burning, singeing of the hair or
gunpowder tattooing.
4. Distance about two to three yards. The wound of entrance has a big central hole with ragged edges and a few
stray wounds of entrance around the central hole. At this distance, there will be no more blackening or burn ing of
the skin, gunpowder tattooing, singeing of the hair and pieces of wads or near the wound of entrance.
5. Distance of four yards. A small group of pellets may penetrate the tissues producing a central core, although
plenty of pellets in a wider dispersion may produced separate wound of entrance. The pellets dispersed about
one and a half the distance in yards in non-choked barrel while in full-choked bore the dispersion is one half less
but there is a wider dispersion in short barrel shotgun.
1. Hemorrhage – Bleeding. It is the loss of blood from the ruptured vessel secondary to trauma or existing
pathology.
2. Direct mechanical injury - This is the direct damage to the tissues
3. Shock - It is disturbance of the balance of fluid in the body characterized by fall in blood pressure, decreases
blood flow or blood volume in the body.
4. Infection. It is the appearance, growth and multiplication of the micro-organism in the living tissues.
5. Embolism. It is the clogging of the blood vessel by foreign bodies such as air or bits of fats or septic embolus
causing blocking to the blood flow to the distal tissues supplied by the blood.
SIR SYDNEY SMITH – founder of the Medico-Legal Faculty at Cairo University and later Regis Professor of Forensic
Medicine at Edinburgh, was one of the leading exponents in studying entrance and exit wounds, powder burns and powder
“tattooing” on human skin and other medical phenomena associated with gun fire.
FORENSIC BALLISTICS
It is the study of Firearm Investigation and Identification of firearms by means of ammunition fired through them. This
is the real branch of the science which the police use as their guide in field investigations. This includes the following:
1. Field Investigations - conducted by the first officers on the case in the field when they investigate a case or
cases wherein firearms have been used. This is a routine job of the investigating officers, and this involves
recognition, collection, marking, preservation, and transmittal of ballistics exhibits like fired bullets, fired
shells, firearms and allied matters.
2. Technical examinations of the ballistics exhibits - This is the job performed by the firearms examiners in the
laboratory. It involves marking of the evidence firearms, test firings of evidence firearms to obtain test
bullets and test shells for comparative purposes, photomicrography under the bullet comparison microscope,
preparation of comparative charts, and the making of reports on the findings and observations of the
firearms examiners.
3. Legal proceedings - Court Trials - wherein the ballistics report of the firearm examiner and the ballistics
exhibits are presented during the trial of the case in a court of justice.
FORENSIC - As applied to ballistics, or to any other subject, suggest a relationship to Courts of Justice and legal
proceedings.
FORUM – It is a Latin word from which forensic was derived, meaning a marketplace, where people gather
for "public disputation" or "public discussion". Thus, the title "Forensic Ballistics" aptly describes the subject under
consideration - the science of investigation and identification of firearms and ammunitions used in crimes. The terms
"Ballistics", Forensic Ballistics" and "Firearms Identification", have come to mean one and the same thing in the minds of
the public, and they can be used interchangeably.
FIREARMS
A firearm is a weapon that fires either single or multiple projectiles propelled at high velocity by the gases produced
through rapid, confined burning of a propellant. This process of rapid burning is technically known as deflagration. In older
firearms, this propellant was typically black powder, but modern firearms use smokeless powder or other propellants.
The term gun is often used as a synonym for firearm, but in specialist use has a restricted sense—referring only to an
artillery piece with a relatively high muzzle velocity and a relatively flat trajectory, such as a field gun, a tank gun, an anti-tank
gun, or a gun used in the delivery of naval gunfire.
Firearms are sometimes referred to as small arms. Small arms are weapons which can be carried by a single
individual, with a barrelbore of up to approximately 0.50 inch (12.7 mm). Small arms are aimed visually at their targets by hand
using optical sights. The range of accuracy for small arms is generally limited to about one mile (1600 m), usually considerably
less, although the current record for a successful Sniper attack is slightly more than 1 1/2 miles.
Firearm (Technical definition) is an instrument that is used for the propulsion of projectile by means of the expansive
force of gases of burning gunpowder.
Firearms or Arm (legal – Sec. 877 of the RAC and Sec. 290 of NIRC) – includes rifles, muskets, carbines, shotguns,
pistols, revolvers and all other weapons from which a bullet, a ball, a shot, a shell or missiles may be discharged by means of
gunpowder or other explosives. The term also includes air rifles, except that are in small in caliber and usually used as toys. The
barrel of any firearm is considered a complete firearm for purposes of Section 877 of the Revised Administrative Code.
Rifle – long rifle bored firearm designed to hit targets at a greater or longer distance, with spiral grooves to fire only a
single shot.
Musket – long smooth bored firearm that is designed to prepare a single shot.
Shotgun – long smooth bored firearm having a barrel of 25-30 inches long and designed to shot birds in flight; long
smooth bored firearm and breech loading designed to fire a number of lead pellets or shot in one charge.
Carbine – s short barrel rifle, having a barrel not longer than 22 inches and it is designed to fire a single shot through a
rifled-bore, either semi-automatic or full automatic, for every press of the trigger.
.22 – minimum caliber - .19 - .18 – if only used as toys, could not be considered as firearm.
Barrel ofany firearm - Possession of any part of a firearm is considered a violation of illegal possession of firearm
(SCRA Dec. 11, 1992).
Firearm is any weapon that uses gunpowder to fire a bullet or shell. Generally, the term is used for light firearms, such
as rifles, shotguns, and pistols. They are often called small arms. Heavier firearms are generally referred to as artillery.
Mechanism
HANDGUN/SHORT ARMS
1. Pistol – a handgun that is magazine feed. It is said that pistols were invented in the Italian town “PISTOIA.” Hence,
the name pistol – arrived in Britain about 1515 as German import.
2. Revolver – A handgun with a corresponding cylinder that revolves before the barrel which consist of different
chambers.
ORIGINS OF FIREARMS
13th Century – development of firearms followed the invention of gunpowder in Western Europe.
BERTHOLD SCHWARTZ – a German monk, and Roger Bacon, an English monk – are both credited with gunpowder
invention.
* Most reference books credit Roger Bacon, English monk and scientist, with the invention of gunpowder in
1248, and Berthold Schwartz, with the application of gunpowder to the propelling of a missile in the early 1300’s. This
powder was that we now call “black powder”.
1118 – Moors used artillery against Zaragoza. Early manuscripts tell o fseveral Moorish campaign in which artillery
was used all dating prior to Bacon and Scwartz.
1245 – Gen. Batu, the Tartar leader used artillery in Liegnitz when he defeated the Poles, Hungarians and Russians.
* It is also often stated that gunpowder was first invented by Chinese were aware of gunpowder and its use
as a propellant long before its advantage became recognized in Europe. It may also assume the Arabs with their
advance knowledge of chemistry at that time.
1247 – one of the earliest recorded uses of firearms in warfare was that o fan attack on Seville, Spain.
1346 – Cannons used by King Edward III of England at Crecy
1453 – Mohammed II of Turkey in his famous conquest of Constantinople.
1500 AD - French Artist LEONARDO DA VINCE as can be gleaned in his sketch of steam powered cannon to
his primitive wheel lock firearm.
* First firearms were inefficient, large and heavy and were not capable of being carried by an individual
soldier hence; the development of cannons preceded that of small arm weapons by almost 50 years.
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CROSS-BOWS >GUNS > MISSILES
Col. Calvin H. Goddard, Md., OS, U.S. Army – Father of Modern Ballistics
Horace Smith – Founded the great firm Smith & Wesson and pioneered the making of breech-loading riffles.
Daniel B. Wesson – An associate or partners of Smith in revolver making.
John M. Browning – Wizard of modern firearms and pioneered the breech loading single shot riffle.
John T. Thompson – Pioneered the making of Thompson Sub-machine gun.
David “Carbine” Williams – maker of first known carbine.
Alexander John Forsyth – Father of the percussion ignition.
Elisha King Root – Designed machinery of making Colt firearms.
Eliphalet Remington – one of the first riffle makers.
John Mahlon Marlin – founder of Marlin Firearms Company.
James Wolfe Ripley – Stimulated the development of the Model 1855 riffled-musket.
Samuel Colt (1814-1862) - of Hartford, Connecticut, produced the first practical revolver bringing it to what most
gunsmiths would agree was its perfect form in the Colt Army 1873 model, which became famous for its .45 caliber.
Other manufacturers followed Colt’s lead: Remington and Smith and Wesson in the US.Adams and Scott-Webley in
BRITAIN, Star, Luger, Browning and Beretta on the CONTINENT, until revolvers were in used in every part of the
world.
Henry Derringer – He gave his name to a whole class of firearms (Rifles and pistols)
John C. Garand – Designed and invented the semi-automatic US Riffle, Cal.30 MI
Oliver F. Winchester – one of the earliest riffles and pistol makers.
John Dreyse (1841) - Invented a breech-loading infantry rifle, the so called needle gun because of its long sharp firing
pin.
Maj. Cavalli of Sardina (1845) - He develop a serviceable breech loading artillery rifle.
Carl Walther (1866) - Develop a reliable small caliber automatic Pistol.
Paul WithelmMauser (1871) - Produced parts of the rifle which had been adopted by the German government.
Sergei Mossin (1891) - Designed the Russian Service rifle.
KijiroNambu (1904) - An army gun designer whose design was first produced by the Kayoba factory.
Charles Dorchester & George Sullivan (1950) - Formed the Armalite business.
1313 – Gunpowder as a Propellant. The age of gunpowder began with its first use as a propellant for a projectile. Such use
has been recorded as early as 1313.
1350 – Small Arms. Gunpowder was first used only in cannons. It was in the middle of the 14 th century that portable hand
firearms were introduced. These guns were ignited by a hand-held hot wire or lighted match.
1498– Riflings. The first reference to riffled barrels appeared. Although it’s important as an aid to accuracy was recognized
by some, it was a year after before riffling was generally used.
1575 – Cartridge. Paper cartridge combining both powder and ball were developed. This greatly speeded loading and
reduced the hazards of carrying loose powder.
1807– Percussion System. The discovery of Forsyth in 1807 that certain compounds detonated by a blast would be used to
ignite the charge in a firearm, for the basis for all later percussion and cartridge to come into general use.
1845 - Rim fire Cartridge. In France, Flobert developed a “bullet breech cap” which was in reality the first rim fire cartridge.
1858 – Center fire Cartridge. The Morse cartridge o f1858 marked the beginning of the rapid development of the center fire
cartridge.
1884 – Automatic machine-gun. Hiram Maxim built the first fully automatic gun, utilizing the recoil of the piece of load and
fire the next charge.
1885 – Smokeless Powder. In France, Vieille developed the first satisfactory smokeless powder, a new propellant which
not only lacked the smoke characteristic of black powder, but also more powerful.
It consists of the number of the helical grooves cut on the surface of the bore, it includes the lands and grooves are
running parallel with one another concentrically.
* Sporting Rifle
As a bullet is fired from a rifle, grooves in the interior of the barrel cause it to spin. The spinning motion stabilizes the bullet and
increases its distance and accuracy. This illustration shows a modern hunting rifle and highlights its main components.
Recent developments - The grooves most commonly used in modern rifling have fairly sharp edges. More recently,
polygonal rifling has become popular, as it seems to produce better accuracy due to the fact that it does not damage the bullet as
badly as conventional rifling. Polygonal barrels also tend to have longer service lives because the reduction of the sharp edges of
the land reduces flame erosion. Higher velocities may be generated due to a reduction of friction and an improvement of the gas
seal between the bullet and barrel. A disadvantage of polygonal rifling is that if simple lead bullets are used, lead from the bullet
tends to accumulate in the barrel (called leading) resulting in a dirty barrel, poor accuracy, and if the leading becomes severe,
excessive chamber pressure which could cause a barrel or locking failure. Polygonal rifling is currently seen on most pistols from
GLOCK and Kahr Arms.
THE RIFLE
The rifle, invented about 1500, had spiral grooves in the barrel that made it more accurate than any previous firearm.
Smokeless powder was developed in the 1800's. Breech loading systems replaced dangerous muzzle loading. Many
improvements since have resulted in high-powered firearms.
Rifle is a gun with spiral grooves in its long barrel that spin the bullet as it is shot. Rifles are usually held against the
shoulder when firing. Soldiers use rifles in battle. People also use rifles to hunt game and to compete in shooting matches.
The rifling in the barrel makes the bullet spin. Without spin, a bullet would not stay pointed forward in flight, but would
tumble over and over. The spinning motion increases the accuracy of a bullet.
Kinds of Rifles
The action on two other kinds of rifles-automatic and semiautomatic-is operated by forces caused by the burning of the
propellant powder in the firing chamber.
1. Bolt-action rifles have an action that resembles a bolt used to lock a door. When the bolt on the rifle is pulled back, the
used cartridge is thrown out and the hammer is cocked. When the bolt is moved forward, it pushes a new cartridge into
the firing chamber.
2. Lever-action rifles are loaded by moving a lever under the breech down and back up. The down movement throws out
the used cartridge and cocks the hammer. The up movement inserts a new cartridge into the firing chamber.
3. Slide-action rifles, also called pump-action rifles, are loaded with a back-and-forth movement of a rod and handle
beneath the front part of the barrel. When the handle is pulled back, the breech opens and the used cartridge is thrown
out. A live cartridge is inserted when the handle is pushed forward.
Automatic and semiautomatic rifles are used mainly by soldiers and police officers. When a rifle is fired, gas is formed by
the burning powder in the firing chamber. The expanding gas drives the bullet out of the barrel. In most modern automatic and
semiautomatic rifles, some of this gas operates the action. When a cartridge is fired, a fresh cartridge is moved out of the
magazine into the firing chamber, and the firing mechanism is cocked.
The M16A2 is the automatic rifle used by the U.S. armed forces. It weighs 8.9 pounds (4 kilograms) when loaded with a
30-cartridge magazine. The M16A2 can fire one shot at a time, or three shots in a single burst. It uses a 5.56-millimeter cartridge.
Rifle cartridges are enclosed in a casing (metal covering) made of brass or steel. Cartridges vary in size according to the
caliber of the rifle. The names of some cartridges include the year the cartridge was put into use. The .30-06 is a .30-caliber
cartridge chosen for use by the U.S. Army in 1906. The classification of some cartridges includes the caliber and velocity (speed)
of the bullet. The bullet from a .250-3000 cartridge has a velocity of 3,000 feet (910 meters) per second.
Modern rifles developed from the crude, muzzle-loading firearms of the 1400's. Rifling of barrels was invented in
Europe about 1500. Smooth-bore firearms (weapons without rifling) could not be depended on to hit targets more than 100 steps
away.
The Jaeger rifle of central and northern Europe was the first accurate rifle. It was developed about 1665. German
immigrants brought jaegers to Pennsylvania in the early 1700's and gave them new features, including longer barrels. The
Pennsylvania-made Kentucky rifle developed from the Jaeger. Some Kentucky rifles were used in the Revolutionary War in
America (1775-1783).
Rifles used round bullets until the 1850's, when more accurate Minie bullets became popular. Minie bullets had hollow
bases and pointed tips and were used in the U.S. Civil War (1861-1865). Improvements of the late 1800's included repeating
rifles, smokeless explosive powder, and jacketed bullets, which have a tough metal cover over a lead or steel core.
THE HANDGUN:
Handgun is a firearm that can be operated with one hand. Other types of guns, such as rifles and machine guns,
require the use of both hands, a tripod (three-legged stand), or a shooting rest.
Parts of a handgun (the frame, the grip, the barrel, the sights, and the action)
The frame is the main body of the gun that connects the other parts. The grip is the handle of the gun, and the barrel is
the metal tube through which the bullet is fired. The lands and rifling (grooves) are alternating raised surfaces and channels
inside the barrel. They cause the bullet to spin and thus make it travel in a direct path.
The shooter uses the sights to line up the handgun with the target. Some sights can be adjusted to help aim the gun
more easily. All handguns made for target shooting have adjustable sights.
The action includes the main working parts of the handgun. It consists of such parts as the trigger, the hammer, and
the cartridge chamber. The type of action determines how the handgun is loaded and fired. The action of every handgun includes
a safety, a mechanism that prevents the gun from being fired unintentionally. The safety ensures that the gun fires when the
shooter squeezes the trigger, but not, for example, when the gun is dropped to the ground.
1. single-action revolvers,
2. double-action revolvers,
3. single-action semiautomatic pistols,
4. double-action semiautomatic pistols, and
5. Single-shot pistols.
Revolvers carry ammunition in chambers in a rotating cylinder. Most pistols are loaded with a magazine containing the
ammunition. The magazine is a metal holder inserted in the gun's butt (thicker end).
Single-action revolvers typically hold six cartridges. An arm near the hammer rotates the cylinder one-sixth of a turn
when the hammer is cocked. This movement puts a cartridge into line with the barrel and the firing pin (part that strikes the
primer to fire the cartridge). After cocking the hammer, the shooter pulls the trigger. The hammer unlocks and falls, exploding the
cartridge. The Colt single-action Army revolver, first produced in the 1870's, is the most famous firearm of this type.
Double-action revolvers, like single-action revolvers, typically hold six cartridges. But, unlike single-action revolvers,
double-action revolvers do not require the user to manually cock the hammer before firing. Instead, the gun is fired by only
pulling the trigger. When the trigger is pulled, a lock that holds the cylinder in place is released, revolving the cylinder and
cocking the hammer. When the next chamber is lined up with the barrel, the cylinder locking bolt is raised into the locking notch,
securing the cylinder. The hammer then falls and fires the cartridge. The cycle is repeated for the next shot.
The main advantage of the double-action revolver over the single-action revolver is that it can be fired rapidly. The
Smith & Wesson military and police revolver is one of the most popular double-action revolvers. This firearm was introduced in
1905.
Single-action semiautomatic pistols are fired by first pulling back a device called a slide to cock the hammer or the
firing pin, which is sometimes called a striker mechanism. When the slide is released, it moves forward and feeds a round from
the clip into the cartridge chamber. When the shooter pulls the trigger, the hammer falls or the striker mechanism is released,
impacting the primer and exploding the gunpowder in the cartridge. The explosion causes the slide to move backward. This
recoil automatically ejects the empty cartridge and recocks the gun. When the slide moves forward again, it reloads the chamber.
The most famous single-action semiautomatic is the Colt .45 automatic pistol. It served as the standard sidearm of the U.S.
armed forces from 1911 until 1985.
Double-action semiautomatic pistols operate somewhat like double-action revolvers. When the trigger is pulled, the
hammer goes through the firing cycle and fires the cartridge. After the initial shot, the pistol begins to operate like a single-action
semiautomatic pistol. The recoil of the first shot forces out the empty cartridge case, cocks the hammer, and inserts a new
cartridge from the clip into the cartridge chamber. Double-action semiautomatics are widely used by sports enthusiasts and
police officers. In 1985, the 9-millimeter Beretta, a double-action semiautomatic pistol, became the standard sidearm of the U.S.
armed forces. Other popular models include the Smith & Wesson Model 39 and the Walther PPK.
Single-shot pistols are used chiefly in international target-shooting competitions. To load a single-shot pistol, the user
moves the operating lever (part that opens and closes the action) forward and down to lower the breech block and to cock the
firing pin. The breech block closes the breech of the gun-that is, the part behind the barrel. After the breech block has been
lowered, the cartridge chamber is exposed. The user then inserts a cartridge into the chamber. Next, the operating lever is pulled
up and back to close the chamber and move the cartridge into the closed position. The pistol is then ready to fire. When the
trigger is pulled, the firing pin drops, exploding the cartridge. The procedure is then repeated to remove the cartridge and reload
the pistol. Famous single-shot pistols include the Hammerli Free Pistol, the Walther, and the Martini.
The first gun operated with one hand was the matchlock gun, which appeared in the 1400's. It was fired by attaching a
burning cord or match to an S-shaped holder called a serpentine. In the early 1500's, the wheel-lock gun was invented. Its metal
wheel struck a spark when it revolved against a piece of pyrite. With the wheel lock, soldiers no longer had to carry flames to
ignite the gunpowder.
During the mid-1500's, snaphance pistols, which were easier to operate than the wheel lock, came into widespread
use. In the 1600's and 1700's, many kinds of gunlocks were developed, including the flintlock.
In 1807, Alexander Forsyth, a Scottish inventor, introduced the percussion system. Percussion-system pistols were
loaded from the muzzle, with a sliding can of priming powder on the breech. Small handguns called derringers are descended
from percussion-system pistols, but are breech loaded. They are named for Henry Deringer, Jr., a U.S. pistol maker of the
1800's.
Rapid-fire handguns - One of the first practical revolvers was the Colt Paterson, patented in England in 1835 by
Samuel Colt, a U.S. inventor. In 1857, the U.S. inventors Horace Smith and Daniel Wesson began producing revolvers that used
cartridges.
The Burckhardt, the first self-loading semiautomatic pistol, appeared in 1893. It had an eight-cartridge clip placed in the
hollow of the grip. George Luger, an Austrian-born inventor, improved the Borchardt in the early 1900's. In 1897, John M.
Browning, a U.S. inventor, patented an automatic pistol that became the basis for later automatics, including the Colt .45.
1. Machine gun is an automatic weapon that can fire from 400 to 1,600 rounds of ammunition each minute. Machine
gun barrels range in size from .22 caliber to 20 millimeters. Ammunition is fed into the gun from a cloth or metal belt, or from a
cartridge holder called a magazine. Because machine guns fire so rapidly, they must be cooled by air. Machine guns are heavy
weapons and are usually mounted on a support.
Operation: In all machine guns, extremely high gas pressure provides the operating energy for the firing cycle. The
cycle begins when the propellant charge in the cartridge case burns. This combustion creates the gas pressure that is used in
the blowback, gas, and recoil operating systems. All three systems fire the projectile through the bore of the barrel, eject the
cartridge case, place a new cartridge in the firing chamber, and ready the mechanism to repeat the cycle.
In the blowback system, the operating energy comes from the cartridge case as the case is forced to the rear by the
gas pressure. The case moves against the bolt (a device that opens and closes the bore), driving the bolt backward against a
spring. The case is ejected, and the compressed spring drives the bolt forward. As the bolt moves forward, it cocks the firing
mechanism, picks up a new cartridge, carries it into the chamber, and the cycle begins again.
In the gas system, the gas pressure drives a piston against the bolt. The bolt is driven to the rear, providing energy for
a cycle like that of the blowback system.
In the recoil system, the bolt locks to the barrel when the gun is fired. These parts remain locked together as they are
forced to the rear by the gas pressure. This movement provides energy to operate the gun.
2. Ground weapons. The 7.62-millimeter M60 machine gun is a major infantry weapon. It is air-cooled and gas-
operated, and fires about 600 rounds a minute. The M60 replaced the Browning machine gun, an important weapon in World
Wars I and II, and the Korean War.
3. Aircraft weapons. By the close of World War I, several types of machine guns were mounted on airplanes. These
types included the Vickers, Maxim, Hotchkiss, Colt-Martin, and Lewis. Some machine guns were synchronized to fire in between
the blades of propellers.
During World War II, fighters and bombers carried machine guns as armament. They also carried automatic cannon up
to 20 millimeters in size. During the Vietnam War, airplanes and helicopters called gunships carried machine guns or cannon.
Today, most fighter planes and gunships carry rockets for air-to-air and air-to-ground use. Bombers use machine guns mounted
in groups of two or four in power-driven turrets. The Vulcan 20-millimeter aircraft cannon has six rotating barrels. It can fire more
than a ton of metal and explosives each minute.
4. Anti-aircraft weapons. The .50-caliber Browning machine gun was used as an antiaircraft weapon during World
War II. It was used alone, or in groups of two or four. Large-caliber automatic cannon that fired explosive shells were also
developed as antiaircraft weapons. The 20-millimeter, Swiss-made Oerlikon gun was used on U.S. Navy ships. It was a self-fed,
self-firing cannon that could fire 600 rounds a minute.
A type of machine gun appeared as early as the 1500's. It consisted of several guns bound together in a bundle or
spread out in a row. A device that was fitted to the gun barrels caused them to fire simultaneously or in series. But little success
was achieved until the Civil War, when many quick-fire guns appeared. Practical, rapid-fire, mechanical guns were used in the
Franco-Prussian War, when soldiers operated them with a crank or lever. The French Montignymitrailleuse and the American
Gatling were among the more successful of these guns.
In 1883, Hiram Maxim, an American-born inventor, developed the first entirely automatic machine gun to gain wide
acceptance. By the time of World War I, many different types of machine guns had come into use.
CLASSIFICATION OF FIREARMS
A. ACCORDING TO GUN BARREL INTERNAL CONSTRUCTION
1. Rifled Bore Firearms - those that contain rifling inside the gun barrel. Riflings refers the lands and grooves such as the
following: Rifle – Pistol - Revolver
2. Smooth Bore Firearms – those that have no rifling inside the gun barrel for the breech end up to the muzzle of the
firearm. Such as the following: Shotguns - Muskets
SHOTGUN – it is smooth bore firearm designed to shoot a number of lead pellets one discharge.
GAUGE – as applied to shotgun indicates that the bore diameter is equal to the diameter of lead ball weighing in
pounds.
1. Military Firearms
a. Pistols d. Shotguns
b. Revolvers e. Machine guns
c. Rifles
2. Pocket and Home Defense Firearms
a. Pistols c. Rifles
b. Revolvers d. Shotguns
3. Target and Outdoorsman known as Sporting
a. Pistols b. Revolvers c. Rifles
2. Pistol 4. Shotgun
a. barrel assembly a. barrel assembly
b. slide assembly b. magazine assembly
c. frame or receiver c. stock group
H. DETAILED PARTS
1. Revolver 2. Pistol
1. Barrel Assembly a. Barrel Assembly
(1) breech end (1) breech end
(2) muzzle end (2) muzzle end
(3) bore (3) bore
(4) rifling (4) rifling
(5) front sight (5) chamber
(6) make (6) interlocking ribs
(7) barrel lug
(8) barrel link
(9) barrel link pin
(10) barrel lead (leed)
The following parts must be removed first before disassembly of the weapon:
- recoil plug - recoil spring - barrel bushing - recoil spring guide - slide stop pin
J. ADVANTAGES
1. Revolver
K. DISADVANTAGES
1. Revolver
bulkier to carry
grip or handle is generally not as good as that of pistol
hard to clean after firing
slower to load
harder to replace worn out parts – it’s a factory job
worn out or poorly made weapon is subject to variable accuracy to improper lining up of cylinder
2. Automatic Pistol
AMMUNITIONS/CARTRIDGES
LEGAL DEFINITION – it may be found in Chapter VII, Sec. 290 of the National Internal Revenue Code as well as in
Sec. 877 of the Revised Administrative Code. It refers to ammunition as s “loaded shell” for rifles, muskets, carbines, shotguns,
revolvers and pistols from which a ball, bullet, shot, shell or other missile may be fired by means of gunpowder or other
explosives. The term also includes ammunition for air rifles as mentioned elsewhere in the Code.
TECHNICAL DEFINTION – Technically speaking, the term ammunition refers to a group of cartridges or to a single
unit or single cartridge – meaning a complete unfired unit consisting of a bullet, cartridge, case, gunpowder and primer. The term
may also refer to a “single round”.
ORIGIN
The term “cartridge” evolved from about the turn of sixteenth century. The earliest small arms ammunition or cartridge
consisted of a pre-measured charge of powder wrapped in a paper. In Webster’s later edition, a cartridge is defined as “A case
capsule, shell or bag of metal, pasteboard, of the like, containing the explosive charge and in small arms and some cannon, the
projectile to be fired. The term cartridge is derived from the word “charta”, the Latin word for paper. Later on, it came through the
French word “cartouche”, meaning a roll of paper, which indicates that the original cartridges were not the brass gilding- metal
tipped units which we are familiar with today.
The use of paper-wrapped powder charged greatly speeds the loading of military weapons, avoided waste of powder
from spillage, and provided a uniform charge from shot to shot. In time, the bullet was either attached faster or more convenient.
“Ammunition” means any unfired assembly of cartridge case, powder, primer and projectile which may be used in a
firearm. Today, it refers to a “file of assembled cartridges” in bulks as in boxes or lots & also used to refer to the supply
a person may be carrying with him.
“Round” refers to a single cartridge.
shotgun cartridges are commonly referred to as “shell” or “shotshell”
rifle ammunition is referred to as “metallics” or “cartridges”.
When an investigator uses a term “cartridge” he invariably refers to revolver, pistol, or rifle cartridges.
The layman uses the abovementioned terms indiscriminately, although as general rule he speaks of “cartridges” when
referring to a pistol, revolver, rifle ammunitions and “shells” when referring to shotguns.
Among the uniformed, the word “bullet” as often misused, as it is commonly used to apply to any sort of any unfired
cartridge. Actually, it is that solid portion of the cartridge which leaves the muzzle of the gun and does the “striking” or
“killing”. The word can properly be used in connection with pistol, revolver or rifle ammunition but other common
designations for the bullet are “projectile” or “ball” is a relic of old muzzle- loading days when all rifle projectiles were
round lead balls.
Rim-fire cartridges may be identified by the smooth base of the cartridge case, which may or may not have a head
stamps are merely letters or design found on the base of the cases that identifies the manufacturer. These rim-fire
cartridges are generally found in caliber .22s. They can be fired in either caliber .22 pistols, caliber 22. Revolvers and
caliber .22 rifles. Rim-fire cartridges can be further classified into:
The abovementioned different classes of small arms cartridges are generally encountered by the Police in the field of
firearms investigation in our jurisdiction. These are commonly used by criminals because they are used in firearms that are easy
to carry, conceal, fire and dispose of.
ARTILLERY AMMUNITION
Artillery includes rocket launchers and such mounted guns as howitzers, mortars, antiaircraft guns, and naval guns.
Most types of field and naval artillery ammunition are called shells. A single shell, like a single cartridge, is known as a round.
Field artillery projectiles range in size from 50 to 240 millimeters and can weigh over 200 pounds (90 kilograms). Most artillery
shells taper to the rear, a shape that gives them greater range. Some have streamlined ogives (nose shields). Others, known as
base-burner shells, have a small amount of propellant burning in the tail during flight. This reduces drag (air resistance).
Some shells are high explosives, which detonate on impact and damage or destroy the target. Detonating the shell's
explosive filler shatters the shell into thousands of fragments. High explosives include TNT; RDX, also known as cyclonite or
hexogen; composition B, a mixture of RDX and TNT; PETN; and pentolite, a combination of PETN and TNT. Other shells contain
mines or small shells that can be expelled at intervals over a specified area or during a certain period of time.
Still other shells are filled with a non-explosive substance, such as a chemical that is poisonous or that produces
smoke or fire. Illuminating, or star, shells light up the battlefield or seascape. A shell with a chaff warhead expels strips of
aluminum, which produce images on a radar screen similar to those caused by aircraft. Such images confuse radar operators
and thus help protect aircraft from enemy attack.
1. Fixed ammunition fired by artillery consists of a projectile, a casing, a primer, and a propellant. Like small-arms
cartridges, fixed artillery ammunition shells are manufactured as complete units.
2. Semi fixed ammunition resembles fixed ammunition. However, the projectile fits loosely into the casing so that the
sections can be separated. Thus, the amount of propellant in the casing can be increased or decreased, depending on
how far the shell is from the target.
3. Separate loading ammunition, also called bag ammunition, consists of separate sections for the projectile, the primer,
and the propellant. The propellant is packed into bags that are placed behind the projectile. The number of bags used
depends on the distance the shell must travel. This type of ammunition is used to fire the heaviest artillery shells over
great distances.
4. Separated ammunition consists of two sections. One section is the projectile. The other includes the primer, the casing,
and a fixed amount of propellant.
5. Guided ammunition can correct its flight in the air after being fired. It often uses pop-out tail fins to steer itself. Most
guided ammunition finds its target by tracking a laser spot on the target. This spot is usually produced by a forward
observer, a person or object forward of the line of fire. Some shells known as smart shells have small radars and
computers in them. These shells can search for and find such targets as armored vehicles or trucks without help.
ARTILLERY-VEHICLE AMMUNITION
Armored-vehicle ammunition consists of projectiles fired by guns mounted on tanks and other armored vehicles. They
have diameters from 20 to 125 millimeters.
A common armored-vehicle penetrator is a projectile with a nose cap of tungsten or another heavy metal. The cap
helps the projectile penetrate opposing vehicles. A high explosive projectile is a hollow-charge warhead. This warhead is hollow
in the front and has an explosive charge in the back. Its explosion converts a copper cone in the warhead to a molten, high-
speed jet. The jet penetrates the target. Another armored vehicle projectile is a long dart made of tungsten or depleted uranium
(uranium with most of its radioactivity removed). The dart travels on a device called a sabot, which breaks away after the dart
leaves the gun's barrel.
Kinds of Shots:
Shotgun cartridges consist of a plastic or paper tube with a brass or steel case at one end. They contain lead or steel
shot instead of bullets.
The caliber of a shotgun is measured by bore, or gauge. The weight of the lead shot required to fit the muzzle of the
gun is the standard of measurement for the bore. If a bullet weighing 1/12 pound (38 grams) fits the bore, the shotgun is called a
12-bore, or a 12-gauge, gun. Popular gauges are 10, 12, 16, 20, 28, and .410.
Some shotguns are named by caliber, as for example, the one that is called .410 gauge shotguns which actually
means .41 caliber. A 12-gauge shotgun has a caliber of .729 inch.
The first shotgun, developed in 1537, was loaded with small shot instead of one round ball. In 1831, Augustus
Demondion patented a cartridge that held small shot. Modern shotguns are single barrels, double barrels, or single barrels with
automatic repeating magazines that hold several cartridges. Repeating shotguns are popular in the United States with hunters as
well as with many law enforcement officers.
SHOT WADS.At a distance of 5-8 yards or more from the place of firing in the approximate direction of fire, one can
sometimes find wads.
CARTRIDGE LIFE
The life of well made metallic small arms ammunitions perhaps 10 years on the average. Some last 5-6 years,
however, ammunitions may lose some of its strength in 5 or 6 years. Some may last 25 years or more depending on the
conditions storage. Damp and warm climates are worst.
In order to prevent the entrance of oil or moisture, it is common practice to varnish the mouth of the case before the
insertion of the bullet and to put a ring of waterproofing around the joint between the primer and the primer pocket.
CARTRIDGE CASES/SHELL
It is a tubular metallic or non-metallic container which holds together the bullet, gunpowder and primer.
It is the portion of the cartridge that is automatically ejected from the automatic firearm during firing and this remains at
the scene of the crime. This is firearm evidence that can help trace a particular firearm from which it was fired.
Annealing – is the process of making cartridge case by heating a brass to become very soft and ductile and very weak:
when it is drawn or otherwise worked, it becomes hard, strong and elastic.
Belted Cartridge – A cartridge, which has a raised belt before the extractor groove. The cartridge seats on this belt,
most “Magnum” cartridge case. Also called a European type primer.
Blank Cartridge – Is a cartridge consisting of the case with its primer, powder charge and a wad to train the powder.
Blank Cartridge Pistol – A firearm without opening in the muzzle, the gas may escape through the hole in the top of the
frame.
Center Pin – serve us a locking device for the cylinder.
Drawing – a machine operation in manufacturing cartridge cases. Is the process of making case by punching discs
from a sheet of brass and then making these discs out into tubes closed to one end.
Guard Cartridge – one loaded with buckshot or a reduced charge ball.
Rolled Crimp – One in which the mouth of the cartridge case is turned inward into a cannelure on the bullet all around
its circumference to retain the bullet at the proper seating depth.
Round – One single complete cartridge.
Ruptured Case – Any cartridge case, which has been split in firing so that the gas has escape.
Short Cartridge – a metallic cartridge loaded with a small shot.
Signal Cartridge – one containing vari-colored luminous balls of the “roman candle” variety.
BULLETS (Projectiles)
Bullet is also knows as PROJECTILE – is a metallic or non-metallic body usually referred to as a bullet that is
completely dependent upon an outside force for its power.
Under this definition, the term may also include projectiles propelled from shotguns although strictly speaking these
projectiles designed for shotguns are called “shot”, “slug” or pellets. In a layman’s viewpoint, a projectile fired from a firearms is
called slug, although what be actually meant is a “bullet”.
The term “bullet” originated from the French word “boulette”, a small ball. In common Police parlance, a bullet may be
called “slug” which is a colloquial term.
CLASSIFICATION OF BULLETS ACCORDING TO MECHANICAL CONSTRUCTION
copper plated steel maybe used instead of gilding metal for the jacket of caliber .45 - jacket of metal patch made of
cupro nickel or gilding metal.
If jacket bullets are used in revolvers, the gun barrel will be loosened or destroyed.
* Another improvement in bullets was the boat-tail in which the name became .30 M1. The “M” stands for Mark but
some contend stands for MODIFICATION.
PURPOSES OF BULLETS
1. .38 – disability purposes
2. .45 – knocking power – subduing a maniac or amok
3. M16 – fatal effects
4. Garand and Carbine – penetration and long range shooting
Cartridges used in weapons other than shotguns are measured by caliber (the diameter of the bullet). Manufacturers
and users of ammunition in the United States have traditionally specified caliber in decimal fractions of an inch. For example,
a .30-caliber cartridge has a diameter of 30/100 inch (7.6 millimeters). However, it is becoming customary to use millimeters
instead. The U.S. armed forces specify caliber in millimeters. Small-arms cartridges are less than 20 millimeters or .78 caliber.
CONVERSION TABLE
Multiply
1. cm to mm - 10.0
2. mm to inch - 0.03937
3. inch to mm - 25.4
7. gram to kg - 0.001
Note:
.0002 second – explosion of a bullet by means of tremendous explosion of burning gases.
Resistance of .38 is 15,000 to 45,000 ft./found.
Buck-shot – it ranges 50 yards
Note:
Ball Bullet – Bullets have soft lead cores inside a jacket.
Cannelure (bullet) – A knurled ring or serrated grooved around the body of the bullet which contains wax for lubrication
in order to minimize friction during the passage of the bullet inside the bore.
Dumdum Bullet – an out-mode and generally misused term – hollow point bullets manufactured in Dumdum, India.
Explosive (Fragmentary) Bullets – Contain a high charge explosive, because of their small size, it is difficult to make a
fuse that will work reliably in small arms ammunitions. For this reason the use of high explosive bullets is usually to 20
mm. and above.
Hollow Point – designed to increase expansion (sometimes called “express bullets”)
Iced Bullets or solidified bullets – super cooled water made as a projectile.
Lead Bullets - Actually a mixture of lead and one or more hardening ingredient.
Metal Cased Bullet – colloquially used to indicate either a metal patched of full patched bullet.
Metal Patched Bullet – any metal-jacketed bullet. Technically, it is a bullet having a metal cup over the base and
extending forward over that portion of the bullet which bears against the rifling, the lead core being exposed at the
nose of the bullet.
Mushroom Bullet – colloquially. Any bullet designed to expand on impact. Technically, a metal patched bullet with
exposed round nose.
Ogive– the curved portion of the bullet that is symmetrical and forms the head of the projectile of ogival shape.
Plated Bullet – a bullet covered with a thin coating of a copper alloy to prevent leading on the inside of the barrel.
Pointed Bullet – more effective ballistically because there is less surface resistance to air, thus the speed is less
retarded and greater velocity.
Soft or Drop Shot – shotgun pellets made of ordinary soft lead made into round pellets.
Soft Point Bullet – expands on striking hence it produces more serious damage and have greater stopping power: from
a high velocity rifle, it will expand upon striking a flesh until it looks like a mushroom, hence, they are often called
mushroom bullet. Such bullets are of little effect than a full-jacketed bullet in revolvers or automatic pistols, because
the velocity is too low to cause the bullet to expand.
Steel Jacketed Bullet – bullet having soft steel jacket, often clad or plated with gliding metal to prevent resting and
reduce frictional resistance in the bore.
Tracer Bullet – a bullet containing a substance inside the jacket at the base of the bullet which is ignited when fired
showing a brilliant “tail light” during its flight. It has an incendiary effect if they strike before the “tail light” base burned
put.
GUNPOWDER
It is a substance or a mixture of substances which upon suitable ignition releases a large amount of chemical energy at a
high and controllable rate, the energy liberation is to convert the propellant into a high of gas.
CLASSIFICATION AND COMPOSITION
Generally, there are two types of powder in small arms. These are:
1. Black Powder (Europeans) – the standard ingredients are: Potassium nitrate 75%, Sulphur 10% and Charcoal 15%.
It’s characteristics are:
a. oldest propellant powder
b. consist of irregular grains and have either a dull or shiny black surface
c. produces grayish smoke and considerable residue is left in the barrel
d. burns with reasonable great rapidity when ignited
2. Smokeless Powder – Nitrocellulose and Nitroglycerine as the major ingredients, mixed with one or more minor
ingredients such as centralite, Vaseline esters, inorganic salts and etc.
Characteristics
a. gray green to black in color and grains are similar in size and shape to the single-base propellants
b. almost all have a perfectly definite shape such as: small squares; discs; flakes; stripes; pellets; and perforated
cylindrical grains
3. Triple based – Nitrocellulose, Nitroglycerine and Nitroguanadine - It was devised in an attempt to compromise between
the low power single based powders and high power but excessive heat of double based powders. The percentage of
nitroglycerin is small, but sufficient to give added power. The nitro-guanidine lowers the flame temperature while still
adding active explosive constituent. One of its virtues is that it is entirely flash less though it does not generate rather
more smoke than the other types.
4. High ignition temperature propellant – Its main constituent is from RDX group of high explosives. It was moderated to
the process of gelatinization and was then developed by Dynamite Noble of Germany in conjunction with Heckler and
Koch for the latter’s G11K2 rifle. This is a caseless cartridge.
Take Note:
Cordite – A British propellant made by dissolving gun cotton and nitroglycerin and adding 5% of Vaseline.
Gun Cotton – A very powerful explosive, like nitroglycerin which is a chemical compound and not a mixture. This is
formed by the action of nitric and sulfuric acid on cotton or any other kind of cellulose.
PRIMER
It is an assembly which ignites the propellant. The primer assembly of center fire cartridges consists of a brass or
guiding-metal cup that contains a primer composition pellet of sensitive explosive, a paper disc (foil), and a brass anvil.
A blow from the firing pin of a small arms weapon on center of the primer cup compresses the primer composition
violently between the cup and the anvil, thus causing the composition to explode. The hole or vent in the anvil allows the
flame to pass through the primer vent in the cartridge case, thereby igniting the propellant.
Rim fire ammunition, such as the caliber .22 cartridge does not contain primer assembly; the primer composition is
spun into the rim of the cartridge case and the propellant is in intimate contact with the composition. In firing, the firing pin strikes
the rim of the case and thus compresses the primer composition and initiates its explosion.
Take Note:
1807 – Alexander John Forsyth conceived the percussion ignition system. He was a Scotch Presbyterian Minister,
chemist and hunter.
First successful priming mixture was one composed of potassium chlorate.
PRIMING COMPOUNDS
1. Corrosive – it has potassium chlorate – IF ignited produces potassium chloride which draws moisture from the air and this
moisture speeds the rusting and corrosion in gun barrels.
CORROSION – chemical wear and tear of the inside of the barrel due to rust formation or chemical reaction by
products of combustion during firing.
EROSION – mechanical wear and tear of the inner surface of the gun barrel due to mechanical abrasion or sliding
friction.
2. Non-corrosive
Mixture 25 yrs. ago:
a. potassium chlorate (initiator & fuel) – 45%
b. antimony (element & fuel) – 23%
c. fulminate of mercury (initiator) – 32%
Germans
Fulminate of mercury – 39%; barium nitrate – 41%; antimony sulfide – 9%; picric acid – 5%; ground glass – 6%
2. INDIVIDUAL CHARACTERISTICS – are those characteristics which are determinable only after the manufacture of the
firearm. They are characteristics whose existence is beyond the control of man and which have a random distribution. Their
existence in a firearm is brought about by the tools in their normal operation resulting through wear, tear, abuse, mutilations,
corrosion, erosions and other fortuitous causes. These are the irregularities found on the inner surface of the barrel and on the
breech face of the breechblock of the firearms as a result of the failure of the tool beyond the control of the manufacturer to make
them smooth as a minor.
1. BULLET IDENTIFICATION
a. No two barrels and microscopically identical as the surface of their bores all posses individual characteristics
markings.
b. When a bullet is fired from a rifled barrel, it becomes engraved by the rifling and this engraving on a bullet fired
from one barrel will be different from that on a similar bullet fire from another barrel. And conversely,. The
engraving on bullet from the same barrel will be the same.
c. Every barrel leaves its “thumb mark” on every bullet which is fired through it, just as every breech face leaves its
“thumb mark” on the base of the fired cartridge case.
a. The first thing to do in the examination of bullets is to conduct a visual examination of the bullets in order to
familiarize with all markings appearing on it.
b. Conduct examination of the bore of the firearm.
c. Determine the conspicuous characteristics appearing on the bullet or any markings appearing therein.
d. Markings appearing on the test bullet No. 1 and does not appear on the succeeding test bullet such markings
should be disregarded. Consequently, such markings are called accidental markings which came from foreign
substances.
e. If the bullet is undersized or the bore of the firearms is badly worn out there will be a cylindrical passage of the
expending gas will appear dark or black in the picture.
WHAT TO COMPARE?
1. Evidence Bullet
2. Test/Standard Bullet
Before proceeding in the examination of the firearm by means of the fired bullets, first identify the particular
firearm through the class characteristics appearing on the cylindrical surface of the bullet.
Manufacturers of firearms make certain marks which may distinguish firearms manufactured by them from
that of other manufacturers. Each manufacturer makes specific number of spiral grooves and direction of the twist of
rifling. A bullet recovered at the crime scene or from the body of the victim may show those marks and on
examination, the examiner may presumptively state from what make of firearm it came from, thus, if one examination
or recovered bullet, it was found out that there are six (6) grooves and the rifling marks are twisted to the left, then it is
possible that it came from a Colt firearm. Smith and Wesson manufacturer has five (5) lands, five (5) grooves and with
right hand twit of rifling. Other class characteristics varied from one manufacturer to another.
3. SHELL Identification
a. The breech face and the striker of every single firearm leave microscopically individualities of their own. The
firearm leaves its “fingerprint” or “thumb mark” on every cartridge which is fires.
b. The whole principle of identification is based on the fact that since the breech face of every weapon must be
individually distinct, the cartridge case which it fires is imprinted with this individuality.
c. The imprints on all cartridges fired from the same weapon are the same and those cartridges fired from different
weapon must always be different.
a. By means of fire bullet you can determine the particular barrel of firearm used.
b. Recovered bullet can tell the type, caliber and make of firearm from which it was fired.
c. Can determine also the condition of the firearm us:
Before proceeding in the examination, conduct a preliminary examination on the cartridge case having a visual
examination on the condition of such cartridge case. Determine whether or not it came from a revolver or from an automatic
pistol and sub-machine guns. Examine those markings that are present on the base portion, the breechface marks, firing pin
impression, the location of the extractor and ejector markings. Check also the markings caused by the chamber of the firearm.
The magazine and the ejector port markings must also be taken into consideration particularly those cartridge cases from gums
having full automatic mechanism.
1. Breechface marks
2. Firing pin impression
3. Ejector mark
4. Extractor mark
5. Chamber mark
1. Impression type – those markings caused by direct pressure contact. (Ex. Breechface mark)
2. Striated mark – those markings caused by sliding contact. (Ex. Minute striations on the cylindrical surface of the bullet)
Take Note:
Abrasion (in the bore) – Scratches caused by using improper cleaning materials, or by firing ammunition with bullets to
which abrasive material was adhering. Normal enlargement of the bore and wearing a way of lands due to the abrasive
action of the bullets.
Accidental Characteristics - Those ate characteristics or marks left by some individual gun that occurred on that
particular shot and may or may not reproduced on any other shots. For example, a grain of sand of shaving of steel
happened to be in the barrel when a shot was fired.
Ballistician – Person whose knowledge in firearms identification is accepted by the courts and other investigation
agencies.
Definitive Proof – after the gun is finally completed, it is again fired with a heavy charge to ensure against accident.
This is the definitive proof and guns passing this test are stamped with still another marked.
Expert - As used in courts includes all witnesses whose opinions are admitted on grounds of specialized knowledge,
training and experience.
Fouling - The accumulated of a deposit within the bore of a firearm caused by solid by-products remaining after a
cartridge of is fired.
Heavy Rusting - Usually called corrosion rather than fouling.
Proof Marks – It is the examination and testing of firearms by a recognized authority according to certain rules and
stamped with a mark to indicate that they are safe for sale and used by the public.
Provisional Proof – the testing of the rough gun barrels and fired with a heavy charge of powder to see if they are
strong enough to be finished and assembled into gun. This provisional proof and a certain stamp are placed on barrels
so tested.
Secondary Firing Pin Impression – Is a mark on the side of the regular impression usually found in pistols.
Shaving Marks – a shaving on the ogive portion of the fired bullet due to poor alignment of the cylinder with the barrel.
This shaving is often found in the revolver.
Skid Marks – When the bullet first starts forward without turning, that before the bullet can begin to turn, it moves
forward a small distance and this makes the front of the groove in the bullet wider than the rear part. This skidding is
more pronounced in revolvers.
Slippage Marks – Scratches of the fired bullet due to badly worn rifling or when the bullet is small or too soft for the
velocity used, there is a tendency for it to go straight forward without turning and it jumps the rifling or slips.
Stripping Marks – scratches on the fired bullet due to worn out barrel.
TECHNIQUES OF EXAMINATION
1. Physical – Evidence bullets, cartridge cases and suspected firearm once submitted by the requesting party will be
physically examined to determine its markings or initials made by the investigator for identification purposes. If no identifying
marks were found the firearms examiner will, before anything, affix his own identifying markings or initials derived from the
names of the requesting party, victim or suspect in that order of priority. The firearm will also be physically examine to determine
its safety devices seeing to it that there is no cartridge inserted in the chamber that will cause accidental firing. Likewise, it will be
examined of its vital parts whether or not it is in operating condition and a tag will be attached for distinction.
Bullets of different class characteristics will be segregated from one another especially the determination of caliber,
number of lands and grooves, twist of rifling, etc. to facilitate its easy final microscopic examination.
Cartridge cases will also be segregated to determine the caliber, type and make of firearm from which they were fired.
Misfired or dud cartridges will also be taken into consideration. Although they may not have any ballistics probative value, yet,
they may give a clue to the solution of a crime.
2. Test Firing – The firearm is test fired before a bullet recovery box in order to obtain test bullets and test cartridge
cases for comparison with the evidence bullets and cartridge cases, respectively,. But before firing, the cartridge will be marked
at the side of the case and on the nose portion of the bullet with letter “T” (to represent test) followed by the last two digits of the
serial number of the firearm of the test to be made (e.g.) T-77-1 to T-77-3 in their order of firing to distinguish the number 1 test
from the number 2 or 3 as the case may be.
3. Microscope Examination – After the recovery of the test bullets and cartridge case, they will be compared with the
evidence cartridge cases under the Bullet Comparison Microscope to determine whether or not the have the congruency of
striations or the same individual characteristics.
Toady, the most widely and reliable instrument in Firearms Identification is the Bullet Comparison Microscope. With
this instrument, the firearms examiner can make a complete examination and comparison of the so called Class and Individual
characteristics that appears on the fired bullets and fired cartridge cases.
This instrument consists of two single tubes fitted with a cross arm and comparison eyepiece, in which the images of
two objects held on its two adjustable stages are fused into one, forming a single image as can be seen on the comparison
eyepiece. The microscope tubes are built as a unit with the comparison eyepiece which has a prism arrangement that brings the
images of the specimen held under the microscopic tubes into a side by side position in the left and right side of the eyepiece
field the eyepiece is threaded for focusing on the dividing line between the two fields.
Under the microscope the two fired bullets or fired cartridge cases can be examined in “juxtaposition” and whatever the
observation and findings obtained during the examination can be photographed for court presentation and also to give the Court
a better understanding and good appreciation of how he came to that conclusion.
Place the two objects on the two adjustable stages under the two microscopic tubes and peep through the comparison
eyepiece. If the objects cannot be seen, adjust the stages through the rock and pinion mechanism. Once the two objects
focused, the next step is to find the similarities existing between the objects either shifting them vertically or horizontally.
Every examiner, no matter how experienced or expert he may be, has had the experience of spending many hours in
the attempt to get the satisfactory and convincing matching in cases where there was every reason to believe that the has the
gun that fired the evidence bullet or shell.
Obtain matching as many as possible, because convincing one’s self and convincing the Court “beyond all reasonable
doubt” are two quite different matters. Te expert must always keep in mind the fact, judges are always keep in mind the fact,
judges are always unpredictable: if some pairs of grooves (or lands) match and others do not, the expert must be prepared to
explain why they do not.
FINDINGS/CONCLUSION
Findings are the bases of conclusion. A conclusion cannot be made without the findings. A good conclusion is always
based on good findings. In comparative examination of the evidence bullet that are found on the periphery running from the
forward shoulder to the base portion (these are surface of the barrel), are discernible with the test bullet or if they have the
congruency, correspondence or intermarriage, then the evidence bullet and the test bullet were fired from one and the same
firearm. For conclusive of findings, there should be at least three (3) tests that should be compared. The first is for preliminary,
the second is for confirmation and the third is for conclusion. This is also true for fired cartridge cases. Although the individual
characteristics of the cases may be found at the base portion where breechface, ejector, extractor markings are found on the
sides that are in contact with the inner surface of the chamber.
Clip or magazine markings may also give discernible markings. Like the ejector or extractor markings if considered
singly may not be a basis for conclusion. These only serve as corroborative characteristics but certainly lack legal significance.
This is so because the case may have these markings even if they were unloaded from the firearm without firing. As a rule, the
point of the examination and comparison is at the area of the primer proper where breechface markings together with the firing
pin impression are located. Primers are softer metals and receive more prominent striation than any other portion of the base.
Conclusion is the opinion gathered from the finding. This is the end result of the examination and should be taken
seriously as it involves the life and liberty of the suspect. When the evidence and the test bullets or cartridge cases have the
same individual characteristics, the competent examiner will conclude that they were fired from one and the same individual
characteristic; the competent examiner will conclude that they were fired from one and the same suspected firearm. If they have
different individual characteristics, certainly, the evidence bullet or case was not fired from the suspected firearm. Where the
evidence has prominent or minor striations that the three tests, it calls for uncertainty and doubt for a positive or negative
conclusion. Only those evidence bullets or cases that have the same individual characteristics may be taken of photomicrograph
for Court presentation.
REQUIREMENTS FOR A POSITIVE IDENTIFICATION
1. Analytical or Torsion Balance – Used for determining weights of bullets and shotgun pellets for possible determination
of type, and make of firearm from which it was fired.
2. Bullet Comparison Microscope – This valuable instrument is specially designed to permit the firearms examiner to
determine the similarity and dissimilarity between two fired bullets or two fired shells, by simultaneously observing their
magnified image in a single microscopic field.
3. Bullet Recovery Box – Consist of a wooden box, 12 “x”12”x 96, with a hinged to cover and with one end open. This
long box is filled with ordinary cotton and separated into sections by cardboard petitions.
4. CP–6 Comparison Projector – An instrument very much similar with the bullet comparison microscope, where 2 fired
bullets or shells can be compared in one setting of the firearms examiner. Also in one sitting, the evidence fired shell
can b4e immediately compared with the test fired shell with the use of this equipment is absolutely no strain of any
kind. No eye strain because the magnified image appears on a large screen and is observed as a vertical and
comfortable viewing distance. No back strain from stooping over a microscope several hours a day. No mental strain
because comparison of evidence is faster, easier and less tiresome, thus allowing a more efficient and productive of
investigative time in the crime laboratory with method that can be seen in the screen can be photographed by any kind
of camera.
5. Filan Micrometer Eye Piece - a measuring microscope to read the width of the land and groove marks and to obtain the
pitch of the rifling in turns per inch.
6. Helixometer – Type of instrument used in measuring pitch of rifling firearms. This instrument is generally used in high
advanced ballistic laboratory. It is not very much needed in a typical police ballistic laboratory. With the use of this
instrument it is possible to measure the angel of twist in a rifle, pistol, or revolver barrel. It is used by the insertion of a
telescope aligned with the axis of the bore. There is an eyepiece and an objective. The scope is mounted on a routable
bearing with graduated discs that permits reading circular measurements, there is a scale graduated in inches. From
the discs we can get the angel of the pitch, this can be combined with the scale reading to compute how many inches
of barrel length would be needed for one complete turn of the rifling. Comparing this figure with those in tables of
manufacturers’ specifications, we can often identify the making and the model of a weapon whose other features have
been destroyed already.
7. Machine Rest - A machine use for testing the accuracy of a firearm.
8. Caliper – an instrument used for making measurements such as bullet diameter and bore diameter.
9. Micrometer – similar in use as caliber.
10. Onoscope – a small instrument sometimes used in examining the internal surface of the gun barrel in determining the
irregularities inside the bore of the gun barrel. It has a tiny lamp at the terminal portion and this is inserted inside the
bore for internal examination.
11. Optical Sight – sight containing series of lenses to form an optical system being contained in one unit. Optical sights do
not necessarily have telescopic properties. The optical system may merely include range indicating, or range
estimating devices, plus the necessary means of adjusting for elevation and wind age.
12. Shadow Graph – Equipment used in firearms identification. It contains a series of microscopic lenses of different
magnification that can be used in examining fired bullet or fired shells to determine their class characteristics and also
for orientation purposes. It greatly differs from the bullet comparison microscope and stereoscope microscope that this
instrument contains a large ground glass, 14 inches more or less in diameter, wherein the observation and comparison
of the class characteristics is done by the firearm examiner. Similarly with the bullet comparison made in the circular
ground glass.
13. Stereoscopic Microscope – unlike the bullet comparison microscope does not have any camera attachment and no
photomicrograph can be taken for court presentation. It is generally used in the preliminary examination of fired bullets
and fired shells to determine the relative distribution of the class characteristics or for so-called orientation purposes. It
can be used also in the close-up examination of tempered serial numbers of firearms. It has two eyepieces and the
lenses and objectives can be manipulated vertically with a series of magnifications. It is one effective instrument for
firearms identification.
14. Taper Gauge – It is used primarily for determining bore diameter of firearms. This instrument is very useful for giving
quick idea as to the caliber of a gun.
15. Telescope Sight – an optical employing the principle of the telescope to enlarge the image of the target.