Forensic Ballistics Overall Notes
Forensic Ballistics Overall Notes
Forensic Ballistics Overall Notes
2. *SAMUEL COLT - Patented the first practical revolver and maker of the colt
peace Maker, a famous revolver in the history.
4. HENRY DERINGER - Gave him name to a whole class of Rifles and Pistols.
5. *MAJOR UZIEL GAL - An Israeli army who designed UZI (Israel) in the year
1950.
8. GEORGE HYDE - A well-known expert in the field of SMG, (a.k.a. grease gun)
developed in 1941. M3A1 (USA)
14.JAMES WOLFE RIFLEY - Stimulated the development of the model 1855 rifle
16.ELISHA KING ROOT - Designed the Machinery for making Colt firearms.
17.*HORACE SMITH - Founded the great firm of Smith and Wesson and
pioneered in making breech loading rifles.
18.*EUGENE STONER - Designed the U.S. M16 Armalite under licensed by Colt
Company from July 1959.
19.L.C. SMITH - Developed shotgun bearing his name now the Ithaca Gun
Company.
1242 A.D.
Roger Bacon published the “De Mirabili Potestate Artis et Nature”
(On the Marvelous Power of Arts and Nature), which noted the Black
Powder Formula.
1200
Roman candle. A hollow tube, strengthened with wire or shrunken
rawhides, and loaded with alternate charges of powder and balls of
tallow wrapped in cloth. It is ignited at the muzzle. Chinese reference
used of Roman Candle is said to be at mid of 1200’s.
1326 A.D.
The f authenticated illustration of gun powder used to hurl projectile in
cannons was demonstrated in Walter De Milimete’s manuscript. In
the same period “The Metrical Life of Robert the Bruce” by John
Barbour also indicates the used of cannon by Edward III at Crecy.
Although not completely authenticated.
1343 A.D.
Cannon locks were used in military as depicted in the Italian Frescoes
by Neri.
CODEX GERMANICUS 600
Translates “Directions for Preparation of Gun Powder”. How to load
the gun and discharge them.
1450
The evolution of the Match Lock Ignition.
1450 – 1500
Serpentine Lock was used to modified the Conventional Match
Lock, using an
S – shaped instead of C – shaped piece with the bottom portion serve as
the trigger.
1469
A drawing from an English manuscript showed a “ribauldegium”, a
multi charged cannon lock weapon
1498
Introduction of rifling and sights became better and breech loaders were
attempted although never succeeded yet even multi shots arms due to
lack of good ignition system.
1500’s
The development of the Wheel Lock, operated in the same principle as
the modern-day cigarette lighter. At mid of 1500’s, “snaphaunce” was
developed.
1575
Paper Cartridge was developed. Ball and powder charged were
wrapped in chemically treated paper to allow the carrying of numerous
pre-measures charges or preloaded rounds.
1750
The development of Breech-Loading Firearms leading to the making
of FERGUSON RIFLE of Major Patrick Ferguson COLLIER Rifle, which
is a flint lock repeating rifle operated on a revolving principles and, the
HALL Rifle patented in 1811 by Col. John Hall and was the first
breechloader adopted by the U.S. Army
1805
The Percussion System. Alexander John Forsyth discovered a
compound that would ignite upon blow they would ignite the powder
charge. In 1840, it replaces the flintlock ignition and was adopted in 1838
by the British and in 1842 by the American.
1835
The first real cartridge was developed; THE FLOBERT CAP. Same as the
BB and was considered the forerunner of 22. Short Cartridge.
Samuel Colt patented the first revolver and marketed in 1872 a breech
loading revolver.
1836
Pin Fire Cartridge was developed by Le Faucheux. A much real pin fire
cartridge was also developed in the same year by Houiller.
1845
Rim Fire Cartridge, Flobert developed the BB (Bullet Breech) cap,
which was considered the forerunner of the .22 cal. cartridge. In the
same year, New Havens Arms Company owned by Oliver F. Winchester,
through the effort of Tyler Henry developed a .44 cal rim fire cartridge of
Henry Rifle.
1846
Smokeless Powder was discovered. It was used in shotgun first in the
year 1864 by Capt. Eschultze of Prussian Army and in Rifle by the year
1884 by M. Vieille of France.
1857
The first patent grant on a center fire cartridge was issued in France.
Later developed the Snider Conversation. The Morse Cartridge was
also developed.
1873
Colt Peace Maker, model 1873, 45 cal. The most famous revolver in
history and legend was manufactured.
1884
Automatic Machine Gun, Hiram Maxim developed the first fully
automatic gun.
1937
M1 Garand was adopted by the American.
1960
Bill Ruger produced his Ruger single shot, which was followed by Clerke’s
design and Christian Sharp’s doppring block system, one of the earliest
and most successful of the breech loading designs. The Christian Sharp’s
design is where the term “sharpshooters” was derived.
What is Ballistics?
Ballistics is the science of the motion of the projectile and the condition that
affects their motion
It is a science for it is an orderly arranged knowledge, which is a product of
series of experimentation, observation, and testing.
Ballistics is not an exact science rather it is applied physics or applied science,
which is subject to change and improvement depending upon the demands of
the modern civilizations.
Ballistics is better to be described as an applied physics for it study the motions
of projectile such as its velocity, trajectory, approximate range, power resistance
to air and other circumstances that will affect its travel.
Initially, it was studied not for the purpose of identifying firearms and
ammunition in relation to a certain crime rather it was earlier studied mainly for
its manufacture, for industry.
Gun makers continuously study and innovate on how to effectively propel a
projectile through the use of firearms from an ordinary single shot to automatic
one.
It was only later that its significance in determining cases through identification
of ammunition that Ballistics was finally applied in the administration of justice
especially on cases involving firearms.
WHAT IS MOTION?
Refers to the mobility or movement of the projectile from the time it
leaves the shell empty. It leaves the gun muzzle and until it reaches its
target or fall the ground.
WHAT IS PROJECTILE?
Is any metallic or non – metallic ball which is propelled from a firearm
It motion can be categorized into three general types.
1. Direct Motion
Is the forwarded motion of the bullet or shots out of the shell by the action of
the expansive force of gases from a burning gunpowder.
2. Rotary Motion
Is the action of the bullet passing through a riffled bore barrel firearm which is
either twisted to the left or to the right.
3. Translation
Is the action of bullet once it hits a target and subsequently ricocheted.
Ricocheted – bouncing of bullet as a result of not penetrating or hitting
the object
3. TERMINAL BALLISTICS.
Is the branch of Ballistics which deal with the effect of the impact of the
projectile on the target.
A. TERMINAL ACCURACY.
It refers to the size of the bullet grouping on the target.
B. TERMINAL ENERGY.
Is the energy or force of the projectile when it strikes the target same as
striking energy.
C. TERMINAL VELOCITY.
Is the speed of the bullet upon striking the target.
D. TERMINAL PENETRATION
Is the depth of entry of the bullet in the target.
4. FORENSIC BALLISTICS.
This branch of ballistics is the product of the application of the ballistics
to law.
The idea comes with the used of the word forensic
The word forensic was derived from the Latin “forum” meaning “market
place” where people gathered for public disputation or public discussion.
When used in connection with the word ballistics or other natural science,
it suggest a relationship to the counts of justice or legal; proceedings.
FORENSIC BALLISTICS.
Is the defined as the study of the motion of the projectile as applied to law or
simply the science of firearm identification by means of ammunition fired through the
gun.
SCOPE OF FORENSIC BALLISTICS.
1. FIELD INVESTIGATION
This is the work of the first officer on the case on the filed.
It is primary a routine job of an investigating officer.
Such work includes recognition, collection, markings, prevention, packing
and transmittal of ballistics exhibits.
In the present practice in cases of highly sensational case or big case are
involved the investigator on case may seek the assistance of the Scene of
the Crime Operation (SOCO).
But everything that will be undertaken by the SOCO shall properly be
coordinated to the investigator on case.
WHAT IS FIREARM?
LEGAL DEFINITION OF FIREARM
Firearms or arms as herein used, includes rifle, muskets, carbines,
shotgun, pistol, revolvers, and all other deadly weapons, to which a
bullet, ball shot, shell, or other missiles maybe discharge b means of gun
powder or other explosives.
This term also includes air rifle, except such of being of small caliber and
limited range used as toys. The barrel of any firearm shall be considered
a complete firearm for all purposes hereof. (Sec. 877 Revised
Administrative Code / Sec. 290 National Internal Revenue Code)
TECHNICAL DEFINITION
Firearms is an instrument used for the propulsion of projectile by means of the
expansive force gases coming from burning gunpowder (FBI Manual of Firearms
Identification)
CLASSES OF FIREARMS
A. Two General Classification of Firearms (According to Interior Barrel
Construction)
1. Smooth Bore Firearms
Firearms that have no rifling (land and grooves) inside their gun barrel
Ex. Shotguns and Muskets.
Gyroscopic Action
- the stillness or the steadiness of the bullet in flight ( straight travel in
flight).
2. Rifled Bore Firearms
Firearms that have rifling inside their gun barrel
Ex. Pistols, Revolvers, and other modern weapons.
2. Shoulder Arms
Shoulder Arms are those types of firearms that were normally fired from
the shoulder.
Rifles – A shoulder weapon design to fire a projectile with more accuracy
through a long-rifled bore barrel, usually more that 22 inches. Just like any
other type of gun, rifles appear in various .
1. Single Shot Rifle
This is the simplest and yet of many types. Some with breech block opened
by means of a lever, chamber feed type, breech block opened and closed by
hand etc.
2. Repeating Rifle
A type of rifle loaded with several cartridges at one time and carries and
cartridge into the chamber when it is ready to be fired, rather than for the
shooter to do it by hand. This can be further divided into: Bolt Action
Type, Lever Action Type, Slide Action Type and Automatic Action
Type.
TYPES OF REPEATING RIFLES.
1. BOLT ACTION TYPE
Bolt – action type may appear as either turning bolt or a straight – pull
bolt type.
The turning bolt types is manipulated by turning the bolt handle first
upward making the bolt in an unlocked position before pulling the handle
to open the chamber causing the cartridge to be exposed and be ready
for another loading and closing before firing.
The straight full action type as its name implies, the bolt is directly pulled
on the rear without being turned.
The chamber will open; loading will follow and then closed again before
firing. The Swiss army called Schmidt – Rubin is a good example of this
type.
2. LEVER TYPE
The name was derived from its manipulation system. It is operated by
downward – forward movement, first of by the lever by hand, causing
opening, cocking and placing of the cartridge in its position for loading.
After which the lever is pull back to closed position moving the cartridge
to the chamber and putting the breech block in place, ready for firing.
Ex. Winchester Model 91
4. AUTOMATIC TYPE
It is a type of rifle in which firing can be made continuously by a single
press of the trigger and while the trigger is pressed.
Firing will only be stop either by the action of the gunner or when
cartridges are all used.
CARBINE
A short barrel rifle, with its barrel, measuring
not longer than 22 inches.
It fires a single projectile though a rifle – bore either
semi – automatic or fully automatic, for every press of the trigger.
MUSKETS
Is an ancient smooth bore and muzzle loading military shoulder arms designed
to fire a shots or a single round lead ball.
SHOTGUN
A smooth bore and breech loading shoulder arms designed to fire a number of
lead pellets or a shots in one charge. (FBA Manual).
A shotgun operates almost exactly in the same way as another rifle.
It only differs in some extent such as the interior barrel construction.
Generally, all shotgun are equipped with a smooth bore barrel designed to fire a
number of lead pellets in a single charge.
2.3 HANDGUNS
Those type of firearms that are designed or intended to be fired using
one had.
Ex. Pistol and Revolvers.
PISTOL
In early firearm history, all handguns are generally called as pistols. There were
three classes of pistols in the period. The single shot pistol, the semi – automatic, and
the revolving pistols now known as the revolver.
*It called pistol because of sliding mechanism.
DISADVANTAGES OF REVOLVER
1. It is more bulky to carry than an automatic pistol.
2. Its grip or handle is generally not as good as than pistol.
3. It is slower to load.
4. It is harder to replace worn out or broken part it is factory job.
5. It is hard to clean.
6. Worn out or poor made weapon is subject to variable accuracy due to
improper lining of cylinder.
*In terms of alignment there is a problem in barrel to cylindrical
ADVANTAGES OF PISTOL
1. It has a better grip – the points naturally.
2. It is more compact for the same firing power.
3. It is easier to load than a revolver (because of the magazine)
4. In case of worn out or corroded barrel, a new can be put in at a little
expense without sending the gun to the factory.
5. It gives greater number of shots that a revolver (7plus 1)
6. It is easier to clean than a revolver.
7. It gives greater firing power and greater case of firing.
8. There is no gas leakage in its operation.
DISADVANTAGES OF PISTOL
1. Ammunition must be perfect otherwise; a jam might experience.
2. A misfire stops the functioning of the gun.
3. When kept loaded for long time, the magazine spring is under tension and may
deteriorate and cause problems.
4. It cannot use blank or reduce loads.
5. It is as poorer trigger pull.
6. The magazine requires a jacketed bullet, which is not as good for practical
use.
7. More dangerous to handle and fire.
8. It is not adopted to reloading.
9. Its mechanism ejects empty shell towards the face of the shooter causing
flinching
10.It throws out empty shells on the ground to remain bree.
11.It cannot be fired from the pocket without jamming.
NOMECLATURE OF FIREARMS AND ITS FUNCTIONS
1. BARREL – Initiates the part of the bullet
2. BOLT – Disengages center pin from allow opening of cylinder and blocks
hammer.
3. CENTER PIN – Serves as locking device for the cylinder.
4. CENTER PIN SPRING – Holds the center pin in a locked position.
5. CYLINDER – Serves as chamber and magazine (for revolver).
6. CYLINDER NOTCH – Helps hold cylinder in the place and aligned for ready
firing.
7. CYLINDER STOP – Stop and holds the cylinder in alignment for firing.
8. DOUBLE ACTION SEAR – Built into weapon to allow double action firing. (for
pistol)
9. EXTRACTOR – Pulls the empty shells to the cylinder simultaneously.
10.FRAME – Houses the internal parts.
11.HAND (PAWL) – Rotates the cylinder when the hammer is locked.
12.HAMMER – Strikes the blow that initiated or ignites primer.
13.HAMMER BLOCK – Safety device that prevents hammer blows from the
primer.
14.MAIN SPRING – Provides energy to the hammer to activate firing mechanism.
15.RATCHET – Helps the withdrawal of the cartridge or shells to the chambers of
the cylinder.
16.REBOUND SLIDE – Returns trigger, activates hammer block, and locked
hammer.
17.SIDE PLATE – Provides access from the internal parts.
18.SIDE PLATE SCREWS – Holds the side plate and yoke in place.
19.STRAIN SCREWS – Controls tension on the mainspring
20.THUMB LATCH – Actuates the bolt from release the cylinder.
21.TRIGGER – Activates the part necessary to fire the weapon.
22.TIGGER GUARD – Guard the trigger to unnecessary action to avoid accidental
firing.
23.TRIGGER SPRING – Provides energy from return movement or rebound slide.
24.TRIGGER LEVEL – Contact rebound slide to return trigger forward.
25.TRIGGER STOP – Prevents excessive rearward movement after hammer
release.
26.YOKE – Pivot connection between the frame and cylinder.
5. LIBERATOR
U.S. Government made smooth bore gun sued in Europe during war
designed to fire an automatic colt pistol cartridge caliber 45. -
6. MULTI – BARRELED GUN
Refers to all types of gun containing a number of barrels.
7. PARADOX GUN
A type of gun which contains lands and grooves a few inch from the
muzzle point.
8. TOOLS
Are those device which resembles a gun designed but are generally used
for construction of furniture.
9. TRAPS
Refers to gun used for trapping animals that are fired to woods.
AMMUNITION
Legal Definition
Refers to loaded shell for riffles, muskets, combine, shotgun, revolvers
and pistols from which a ball, shot shell or other missiles maybe / fired
by means of gun powder or other explosive.
The Term also includes ammunition for air rifles as mentioned elsewhere in the
code.( Chapter VII, Sec. 290 of NIRC as well as Sec 877 RAC)
Technical Definition
Refers to a group of cartridge or to a single cartridge.
Cartridge is a complete unfired unit consisting of bullet (ball), primer
(cap), cartridge case (shell) and gunpowder (propellant).
Origin
The word cartridge was derived from the Latin word "Charta' meaning-
a "paper" and also from French word “Cartouche" meaning a rolled
paper.
This only indicates that the first type of cartridge was made up of a rolled
paper.
It was about the turn of the 16th century that the term 'cartridge" comes to use
Shotgun Cartridge
It refers to a complete unit of unfired cartridge consisting of the pallets,
primer, case wads and gunpowder (Fig.9b and 1 1).
Gauge of Shotgun
Compare with other types of firearms, shotgun has very unique
characteristics in terms of its diameter designation both for its
firearms and cartridge use
The unit of measurement used in shotgun is expressed in Gauge
This is determined by the number of solid lead balls of pure , each with
diameter of the barrel that can be prepared from one pound of lead.
lf for instance, we have a 12 balls that can be made out of one pound of lead
and each ball exactly fitted to the inside of the barrel of a shotgun, the gun is
called a 1 2-gauge or 12 bore shotgun.
Each lead ball for 1 2-gauge should therefore weigh 1 /12 of a pound.
Such is applied in almost all type of shotgun in which the diameter is express in
a thousandth of an inch
At present the 10-gauage shotgun is considered with the biggest diameter while
the.410 as the smallest one.
Listed below are the equivalents of diameter in gauge to inch.
Gauge Inch
10 .775 inch
12 .729 inch
16 .670 inch
20 .615 inch
28 .550 inch
410 .410 inch
TYPE OF SHOTS
1. Soft or Drop Shots
Made by pure nearly pure lead, to which a small amount of arsenic has
been added to make it take on the form of a spherical drop as it falls
down the shot tower.
This type is easy to deformed or flattered, loose their velocity quicker, low
penetrating power and string out more.
2. Chilled or Hand Shot
Is a type of shot with a small of antimony mixed with lead to increase
hardness.
It does no deform easily, better patterns, less string and more uniform
velocity and penetration.
3. Coated or Plated Shot (lubaloy)
also called as "lubaloy" shot. A chilled shot coated with thin copper through
electroplating design for greater strength and elasticity, great resistance to
deformation and leading and better pattern.
Buck shot- a large size lead shot for used in shotgun
Ammunition- complete unfired unit (compose of bullet, primer, cartridge &cartridge
case)
Bullet – metallic built in upper part (pinaka tingga)
Cartridge – part of ammunition
Cartridge case – lalagyan
Bullet and projectile are same. Refers to object to throw
BULLET
The word "Bullet" was derived from French word "Boullette" which means a small
ball.
This term is generally used when we are referring to projectile fired from small
arms, which has a variety or form, especially during the earlier history.
In a more technical sense, bullet refers to a metallic or non-metallic cylindrical
ball propelled from a firearm it is sometimes called as shots or slugs.
Bullets have various types depending upon their specific nature and purpose. In
general bullet can be classified as either Lead or Jacketed
1. Lead Type
- Is a type of a bullet that I basically composed of lead metal
- It’s used was due to its density; having a good weight is a small size
and easy for casting.
- At present it is being mixed with a small amount percentage of antimony or
zinc in order to add harness and prevent "lead fouling.”
- In some cases, lead metal are used as core for jacketed type of a
bullet.
- Commonly used in revolvers and in modern construction having its
rear section jacketed, leaving the lead core exposed.
2. Jacketed Type
- Is a type of bullet consisting of the regular lad core, coated with a
copper alloy in order to prevent lead fouling of the barrel and is
generally used in pistols and other high-power guns.
According to their Maximum Effect to their Targets (See Fig.12)
1. Ball Type
Is a type of bullet, which is intended for anti- personnel and general
use.
2. Armor Piercing
Is a type of military bullet designed to penetrate light steel armor.
Its mechanical construction makes it capable of penetrating through some
light vehicles.
It is formed by a hard steel core covered with a jacket thus, giving its core
the optimum power of piercing while its shape has the optimum shape for
accurate fight.
It was first patented in about 1903 by Roth of Vienna, although, it
was largely introduced for snipers countering the small armor
shields in the year 1914-1918.
3. Explosive Bullet
Is a small bullet containing a charge of explosive, which will
detonate on impact.
4. Incendiary Bullet
Type of military bullet used to cause fire in a target, generally
designed to use by aircraft armament in order for the fuel tanks to
ignite.
It is constructed by having front of the bullet be filled with while
phosphorous, a chemical capable of spontaneous ignition when comes into
contact with air.
5. Tracer Bullet
A type of military bullet capable of leaving visible marks or traces
while in flight giving the gunner the chance to observe the strike of the
shot or make adjustments in the event of miss.
It resembles a ball type, although the rare portion of the core removed and
the space filled with mixture of magnesium powder, barium nitrate and
metallic salts to give the desired color of the flame or smoke.
MISCELLENEOUS TYPES OF BULLETS
1. Baton Round
Is the proper name used when referring to a "rubber bullet".
This type of bullet was first developed for the Hong Kong Police and
was of wood, due to its ability to split on impact with the ground
thus, possible of inflicting wounds it was later replaced by a rubber.
This is generally a plain cylindrical rubber or plastic used in 12-bore, 26mm
or 37mm riot gun and fired by a lot powered charge.
2. Compound Bullet
A type of bullet having its core of dense metal covered with jacket of
lighter metal which does not bring lead into contact with the rifling
on the weapon and which was designed by Major Rubin of the Swiss
Army in the year 1880's.
3. Discarding Sabot
is special type of bullet in which a solid ball place in a case which
separates when the bullet was fired giving an extra velocity to the
bullet.
A bullet of this type was manufactured by Remington, and it was given
the name “Accelerator Bullet”.
4. Dum- Dum Bullet
It is a type of bullet designed in India in the year 1890s by Captain
Bertie Clay.
It consisted of service ball having its nose expose due to a trimmed
jacket to the back. Now the term is loosely used in describing any
expanding bullet.
5. Frangible Ball Type
Is a type of bullet designed for training purposes especially for aerial
targets.
It does not cause any damage to the target rather leaving a paint
mark for the purpose of assessing the gunners.
6. Flechette
A dark — like solid projectile, stabilized in flight by fins.
It was in used as early as 1914 and at present the cartridge for 12
gauges is loaded with 20 steel flechettes
7. Heel Bullet
Is a type of bullet commonly used in pistol having its rear portion
reduced in diameter in order to fit into mouth of the shell, thus
making the rest of its part appears flush with the mouth of the shell.
8. Hallow Point
Is a type of bullet in which the nose is drilled out to the certain depth
leaving a hole.
The purpose is to be able for the bullet to deform upon impact
making a "mushroom".
9. Lethal Ball
British term used when referring to a single shot used to issue to the
members of the home guard anti personal use during World War
Two.
10.Multiple Bullet
Is the term applied to a number or two (duplex) or three (triplex)
bullet formed a cartridge it was patented to the early 1990s by Gorge
Luger.
11.Soft Point
Refers to any of bullet having its jacket short that have nose in
exposed thus capable deforming upon the impact and it is common
for hurting purpose.
12.Spitzer Bullet
Is the term to use by the American AND British sportsmen when
referring to a pointed bullet.
13.Streamlined Bullet
Is a type of bullet that has front section tapered to a point and its rear
section tapered to as smaller diameter thus reducing the Base Drag.
Cartridge Case
3. It provides gas seals at the breech against an unwanted escape of propellant gas
upon firing.
5. Acts as the insulator between the propellant and the hot walls of the chamber in
a rapid firing firearms.
1. Base = the bottom of the cartridge case which contain the head stamp
marking on the base of the shell containing the caliber, manufacturer and in
some cases including the data, trade name, and batch number.
2. Rim = is the part of the cartridge designed to limit he forward movement of the
cartridge to chamber.
3. Exacting grooves = is the circular grooves near the rim of the shell designed for
automatic withdrawal of the case the chamber.
4. Primer Pocket = is that part of the shell which provides the mean for the
primer to be put in the central position.
Its function I extended to
a. Hold the primer in place
b. To provide means to prevent the
escape of gas.
c. To provide solid support to primer
anvil.
5. Body = is the cylindrical part of the shell
which house the gunpowder.
6. Shoulder = that part of the cartridge case which support the neck of the cartridge
which is evident in a bottleneck type.
7. Cannelure = is the cylindrical groove in the outer surface of the cartridge case
designed to secure the shell to the chamber as well as prevent bullet from
being push down to the powder charge. In some instance it is even being utilized
for identification.
8. Neck = is that part of the shell which is actually occupied by the bullet. This is obvious
in a bottleneck type of shell but not with the straight type.
9. Crimp = is the cylindrical groove on the mouth of the shell designed for two
purposes:
1. Is to hold the bullet and prevent it from being pull out from the shell
2. to offers resistance to the bullet out of the neck to ensure burning of
the gun powder.
10.Vent or Flash hole= is the hole at the bottom of the primer pocket as the
passage way for the priming mixture to impart an ignition to the propellant
charge.
PRIMER
The term "lock" was the one used during the ancient time when referring to
ignition system.
The earliest of these is the "match lock" also referred to as refined "serpentine
lock" with S-shaped piece of metal pivoted on the stave, the forward end
holding the hump fiber treated with saltpepper, twisted and tied by a thread to
retain the twists to make it slow burning.
It burns at about 3 to 5 inches per hour.
The matchlock was later superseded by a "wheel lock" in the early years of the 16th
century.
This ignition system is comparable to the modern principle of our cigarette
lighters.
A roughened wheel, driven by a spring that needs to be the first wound up or spanned
producing sparks igniting the priming powder and passed through a touch hole burning
the powder charge.
Fifty, years later, the "flint lock" ignition system was developed (fast known "snap-
lock").
In this system a simple mechanical fire striking lick called "snaphaunce" replace the
wheel mechanism and an iron right-angle pan cover hinged over the priming
pan constituted the flint lock.
The hinged will be stricken by the cock upon release of the trigger, causing the hinged
cover to be thrown back, exposing and igniting the priming powder by the sparks
produced by the scraping of flint along the iron.
This system was used until the start of the 19th century when the percussion system
was finally been developed.
Alexander John Forsyth, a minister of Belhelvie in Scotland, known as the father of
percussion system developed a better system of ignition in the year 1805.
He devised a formula composing of mercury fulminate that would easily ignite
upon a single struck.
The percussion system was spread and almost totally replaced the flintlock in
the year 1840.
This led to the making of the famous percussion cap of Joshua Shaw in 1814 and
finally adopted by British Army in the year 1838 and by the Americans in the
year.
1. Primer Cup = is the brass gilding metal cup which contains the priming
mixture, the disc and the anvil.
2. Priming Mixture (percussion powder.) = is the highly sensitive chemical
compound which ignites by the mechanical blow of the firing pin. Also called
as percussion powder.
3. Anvil = is that portion of the primer which provides solid support and absorbs
the blow of the firing pin causing friction that would initiates ignition
4. Disc = is a the paper or foil which is pressed over the priming mixture in order
to protect it from moisture.
Types of Priming Mixture Compound
1. Corrosive
One containing potassium chlorate which when ignite produce moisture
causing the formation of rust in the bore of the firearm.
Other components are Antimony sulfide and mercury fulminate.
2. Non- Corrosive
One which is designed for less chances of rusting by replacing the
potassium chlorate with barium nitrate.
Berthold Schwartz
Black powder, the oldest known explosive from saltpepper (75%), charcoal
(15%) and formula varies in percentage and even different country throughout the
world.
This mixture is being ground into fine called “Serpentine" which was said to have
been used until middle of the 16th century.
After such form, a "corned powder" was used to replace serpentine, for being
more stable. But due to its high sensitivity leading to accidents modifications
had been made to develop other forms.
Some used potassium nitrates while the other used sodium nitrate.
But whatever forms or composition of black powders there is generally great
disadvantage of this powder.
It creates a dark smoke and causes fouling.
This creates a problem not only to the gunner but also to the gun itself
These problems in the used of black powder was later remedied with the
introduction of the smokeless powder. According to Harrison Captain E.
Schultze of the Prussian Army, made the1st successful used of smokeless
powder in shotgun in the year 1864(Although historically nitroglycerine
compound was first discovered in 1846).
The basic ingredient used for smokeless powder is a nitrocellulose that was
first produced by adding a nitric acid to cellulose fiber.
Later, M. Vieille of French developed the first smokeless powder for riffle in the
year 1884 and named it "prouder B." taken after Gen. Boulangers name.
In 1887, Alfred Nobel invented a smokeless powder with (nitroglycerine 40%
and nitrocellulose (60%) as the main composition and called it "Ballistite".
In Great Britain, they utilized picrid acid in addition to cellulose powder which
they called "Lyddite" and in Germany TNT (tri-nitroleleune) was the one used,
more powerful than picric acid but much difficult to detonate.
Also in the year 1889, Prof. Abel, a British War dept. Chemist developed
“Cordite" a smokeless powder with same composition as Nobel in the form of
cords or sticks.
And in early 1890's smokeless powder had replaced black powder and became
uniformly used worldwide by the year 1900.
FIREARM CHARACTERISTICS
All barrel irrespective of the type of the weapons for which they are made, are
manufactured from a solid piece of metal.
The metal from which the barrel is made is carefully selected for its chemical and
metallurgical properties, thus assuring a high-quality product after the various
machine operations and heat treatment are completed.
A. Drilling
A special deep-hole is used through the center of which lubricating oil is
forced under pressure.
This operation results to a comparatively rough hole of uniform diameter from
one end of the barrel to other.
At this stage, the interior surface of the barrel will bear numerous sears and
scratched resulting from the irregular cutting of the drill and the metal chips
which mark the finish
B. Reaming
In the process some of the scars or scratches left by the drilling
operation are move. The reamer removes metal from the entire
surface because it is slightly larger in diameter than the drill, which
completes the bore operations.
It includes roughly, finishing and burnishing reamer to have a smooth
bore barrel.
C. Rifling
This process necessary for the making of the helical groves inside the
barrel and such can perform in any of the following methods.
1. Hook — cutter system (cutter)
2. Scrape - cutter system (scraper)
3. Broaching - system (broach)
4. Button — system (button)
D. Lapped
This is the polishing operation in which a lead closely fitting the inside of
the barrel is drawn back and forth on a rod carrying with is a polishing
compound.
This will remove large imperfection on the side surface of the barrel both
to the lands and the grooves.
What is important about this process is that no matter how many times
we polish or finish large imperfections maybe eliminated but not the
minute imperfections making a series of striations that will be impressed
on every bullet that will pass through it.
This is the basis for which firearms is identified.
Just like any barrel of every firearm, the breech face also bears with it the same
important. It is that portion of the firearms against which the shell or the
cartridge case and the primer is pressed background every time that a
cartridge is fired in the chamber.
If these things happen the base of the cartridge will be marked by the gun.
This is due to the fact that every breech face of a firearms just like the barrel are
made up of a harder metal than any cartridge case or bullet, thus the
principle that when a softer surface comes in contract with a harder on it as
always, the softer surface that characters that harder surface has.
Type of Characteristics in Firearms
A. Class characteristics
- are those properties or attributes of a firearms which can be
determined even before the manufacture of the gun.
- This is true for such characteristics are a manufactures designs or
specifications and security.
1. Bore diameter (caliber or gauge)
- it is diameter to which the bore was reamed.
- The distance measure between two opposite lands inside the bore in a
hundredths or thousandths of an inch. In most express in either caliber in
inch or in millimeters such Cal. 22, 25, 30, 32, 38, 380, 357, 44, 45, 50,
r etc., Or 55.55mm, 6.35mm, 9mm, 11mm, etc.
- In shotgun they are either in gauge or in inch, such as in 10-gauge, 12
gauge (.729), 20 gauge (615), 24 gauge (579), 30 gauge (.537) 36
gauge (.506) and the smallest which is 410.
2. Number of lands and grooves
- The number of lands a groove inside the barrel of a given firearms are
always the same or equal. It may run from 3-8, but the most in the
modern firearms are five and six.
- Lands are the elevated portion of the bore of the firearm.
- Grooves are the depressed potion of the bore between the lands.
3. Width of the lands
- is dependent upon the bore diameter of the gun, grooves, width and
number.
- The lands are the remainders of the circumference after subtracting all
the grooves width.
4. Width of the Grooves
- is measured as the shortest distance between the two dies or edge of a
grooves.
5. Direction of twist
- rifling inside the barrel of the gun is either twisted to the left or to the
right which cause bullet to rotate as it passes through the bore, in order
to ensure gyroscopic stability in its flight.
6. Pitch of Rifling
- It is the measure of the twisting of the hands and grooves .
- It refers to the measure of the distance advance by the rifling in order to
make a complete turn inside the barrel.
7. Depth of the Grooves
- the grooves depth if measure on a radius of the bore.
- Grooves are usually few thousandths of an inch deep, which equal to
the height of the lands.
B. Individual Characteristics
- are meant for those characteristics which are being determined only after
the firearm was already been manufactured.
- They are the product of machine imperfections and some later due to the
used of the firearms.
Types of Rifling
1. Steyer Type
is the type of rifling having four (4) lands and grooves right twist and
the width of the lands grooves (4 RG=L)
2. Carbine Type
rifling having (4) lands and grooves, right twist, the width of the
grooves is two (2) times the width of the lands (4RG2X).
3. Smith and Wesson
rifling having (5) lands and grooves, right hand twist, the width of the
land and grooves are equal. (5RG=L)
4. Colt
type of rifling having six (6) lands and grooves, left twist. the width of
the grooves is twice (2) the width of the lands (6LG2X)
5. Browning
type of rifling having (6) lands and grooves, right hand twist, the width
of the grooves is twice the width of the lands. (6RG2X)
6. Webley
Rifling having seven (7) lands and grooves. right hand twist, the width
of the grooves is three time larger than the boarder of the lands.
(7RG3X)
7. Winchester
Rifling having six (6) lands and grooves, right hand twist, the width of
the grooves is three time larger the width of the lands.
Individual Characteristics
in firearms are usually determined by the test firing which will give us both
the test bullet and the test shell that will show the individuality of its
property based on the left marks on every bullet and shell fired from it.
Such marks are so minute that the use of the lens with high magnification is necessary
to discover individuality.
Marks left on fired shells or fired bullet categorized as to either accidental or
is are generally repetitive.
Accidental marks are those marks that may bare some importance to the
investigation but are considered of not much value in the identification of
the particular firearm or weapon since they are not regularly formed in the
operation of the gun.
On the other hand, Repetitive marks are those marks, which are very useful in
identifying a firearm. They show identity
1. Land Marks
left on a fired bullet caused by its contact to the elevated portion
(lands) of the bore of the firearm.
It appears as slight depressions or scratches the cylindrical surface of
the fired bullet.
This considered as one of the most important mark found on a fired
bullet used for the purposes of Identification.
2. Groove Marks
marks found on a fired bullet caused by the grooves of the barrel which
is the same number as that of the landmarks.
3. Skid Marks
Marks that are generally found on fired bullet from a revolver . It is more
or less located at the anterior portion of the fired bullet due to its
forward movement from the chamber to the barrel of the gun before it
initially rotates.
4. Stripping Marks
Marks found on those bullets fired from a "loose fit" barrel wherein the rifling
are already been badly worn-out.
Worn- out in the rifling of the firearms can be cause by either chemical
reaction brought about by rust (corrosion) or through excessive use
(erosion)
5. Shaving Marks
marks commonly found on bullet fired from a revolver cause by its
forward movement to the barrel that is poorly aligned to the cylinder.
6. Slippage Marks
marks found on fired bullets passing through either on oily or oversize
barrel.
1. Given a fired bullet to determine the caliber, type, make of firearm from which it was
fired.
2. Given a fired shell to determine the caliber, type, and make of firearm from which it
was fired.
3. Given a fired bullet and suspected firearm, to determine whether or not the fired bullet
was fired from the suspected firearm.
4. Given a fired shell and a suspected firearm.
5. Given two or more fired bullets, to determine whether they were fired from one and the
same firearm.
6. Given two or more fired shell cartridge case, to determine whether they were fired from
one and the same firearm.
7. Given a suspected firearm, to determine where it is serviceable or not.
PROBLEM NO 1
Given: A fired bullet.
Objective: to determine the caliber, type and make of firearm from which it was fired.
Procedure:
a. Identify the bullet based on its various features such as type, shape and
design.
b. Use a caliper to measure the base diameter of the bullet in determining its
caliber or simply used standard bullet at hand and match the base of the
bullets.
c. After determining the caliber of the fire bullet, examined its cylindrical surface
for the landmarks and groove marks. Identify the type of rifling by determining
the number of lands and grooves, the direction of twist, the pitch of riffling, the
width of the lands and grooves and the depth of landmarks.
PROBLEM NO. 2
Given: A fired shell/cartridge case
Objective: to determine the caliber, type and make of firearm from which it was fired.
Procedure:
a. Determine the caliber of the shell utilizing the caliper to measure its body
diameter or the diameter of the mouth of the shell or match the fired shell with
a standard shell.
b. Check on the base of the fired bullet for the head stamp. This part of the
shell will give the examiner information as to the caliber, the maker, and at
certain case even the date of its manufacture.
PROBLEM NO. 3
Given: A fired bullet and a suspected firearm.
Objective: to determine whether the fired bullet was fired from the suspected firearm.
Procedure:
a. Examine the fired bullet as to its caliber, type and make applying the
procedure in problem no. 1
c. Test-fire the suspected firearm using the bullet recovery box. Use at least (3)
cartridges with the same caliber and make as the fired bullet. Make sure to
mark the cartridge with letter "T1, T2, and T3" as the case maybe plus the last
two digit of the serial number of the suspected firearm.
d. Get the test bullet from the recovery box and identify its general
characteristics to determine probability with the fired bullet.
e. Match the fired bullet with the test bullet using the bullet comparison
microscope or forensic comparator microscope.
PROBLEM NO. 4
Given: A fired shell and a suspected firearm.
Objective: to determine whether or not the fire shell was fired from the suspected
firearm.
Procedure:
c. Test-fire the suspected firearm using the bullet recovery box. Used at least
three (3) cartridges for test firing. Make sure to mark the cartridge with letter
"T1, T2 and T3" as the case maybe plus the last two digit of the serial number
of the suspected firearm.
d. Get all the test shell and identify its general characteristics to determine
probability with the fired shell.
e. Match the fired shell with the test shell using the bullet comparison
microscope or forensic comparator microscope.
PROBLEM NO. 5
Given: Two or more fired bullets
Objective: to determine whether or not they were fired from one and the same
firearm.
Procedure:
a. Identify those bullets as to their caliber, type and make applying the principle
in problem no. 1 don’t forget to mark the fired bullets)
b. Bullets of the same caliber, type and make should be compared at the bullet
comparison microscope.
c. Those fired bullets that show a magnified image of similar characteristics will
be considered fired from one and the same firearm, while those that would not
match positively were fired from different firearm.
PROBLEM NO. 6
Given: Two or more fired shell.
Observe: to determine whether they were fired from one and the same firearm.
Procedure:
a. Identify each fired cartridge case or shell as to their caliber, type and make
applying the procedure in problem No.2 (don't forget to mark each fired shell.)
b. Compare each fired shell of the same caliber, type and make using bullet
comparing microscope. Those fired cartridge case having similar individual
marks (striations) will proved that they were fired from one the same firearms
and non- identity of their individual marks would consider them to have been
from different firearm.
PROBLEM NO. 7
Given: A suspected firearm.
Procedure:
a. Examine the suspected firearm, its caliber, type and make and its condition.
1. Firearm identification is actually refined tool marks identification. It means that the
basis of identification of firearm is based on minute imperfection cause by final
polishing of the tools involved.
2. The natural wear and tear of the tools involved. Every firearm is not permanent for
they are subject to deterioration or won out.
3. When the softer surface comes in contact with the harder surface, it is always the
softer surface that will be engraved or marked by whatever impression or marks
present on the harder surface. This is true in a sense that every firearm is made up of
harder material than any bullet or shell of the cartridge.
4. The fact that no two things are absolutely identical or alike. There can be some sort of
similarity in general properties but not on the individuality or minute imperfections.
1. No two barrels are microscopically alike or identical as to the internal bore construction;
all barrels possess individuality or characteristics marks of their own.
2. When a bullet is fired from a rifled gun barrel, it becomes engraved by the rifling
characteristics of that barrel with varying minute details. It means that bullet fired from
one barrel will have an engraving different from that of another bullet fired from
another firearm and conversely, bullets fired from same firearm will bare same
engraving as those that can be found on the barrel.
3. Every barrel leaves its "thumbprint" on every bullet fired on it.
1. The breech face and striker (or firing pin) of every single firearm has microscopic
individualities.
2. Every firearm leaves its" fingerprint" of thumbprint" on every cartridge it fires.
3. The whole principle of identification of shells is based upon the fact that since the
breech face of every weapon must be individually distinct, the cartridge cases that is
fires are imprinted with this individuality. The imprints of all cartridge cases fired from
the same weapon are the same, and those on cartridge cases fired from different
weapon are different.