The Micro UZI Pistol is currently banned under a Maryland law that states that any gun defined as an assault pistol is unlawful to possess unless registered prior to August 1, 1994.

The 1994 federal assault weapons ban that expired in 2004 had banned all UZI firearms.

Measuring less than 10 inches long and weighing under 10 pounds when fully loaded, the UZI pistol is relatively easy to carry and conceal.

The UZI was developed by and named after Israeli army captain Uziel Gal. The first prototypes appeared in 1950 and were soon issued to select Israeli army units for field testing.

The UZI .22 Long Rifle is not a regulated firearm in Maryland and is therefore legal to own. The legal status of the gun will not be changed if Gov. Martin O'Malley's proposed gun control legislation passes.

Police said they found a bag carrying a fully-loaded UZI B .22 rifle, similar to the model pictured, near Dayvon Green - the University of Maryland graduate student who killed his roommate and then himself with a handgun on Tuesday. The UZI B .22 rifle was not used in the shooting.

The UZI .22 Long Rifle is designed to look like traditional UZI guns, but uses a .22 Long Rifle cartridge, a popular caliber of ammunition among small-game hunters.

The Bushmaster XM-15 is considered a regulated firearm in Maryland. Gov. Martin O'Malley's proposed gun control legislation defines the Bushmaster semi-automatic rifle as an assault weapon.

Bushmaster semi-automatic rifles were designed for military and law-enforcement.

The Bushmaster .223 caliber model XM-15-E2S rifle was the primary weapon used by Adam Lanza, the shooter at Sandy Hook Elementary School that killed 20 children. It is similar to the model pictured here.

Shotguns are designed to fire batches of small projectiles. They cause the most damage when used at close range.

Gov. Martin O'Malley's proposed gun control legislation would not change the way shotguns are treated by the state. Most shotguns -- including the one pictured here -- are considered "unregulated firearms," meaning they do not require a state background check to buy.

In the Aurora, Colo., theater shooting, James Holmes used a Remington 870 pump-action 12-gauge shotgun, along with a Smith & Wesson assault rifle and a .40 caliber pistol.

While the assault rifle received a lot of media attention, many weapons experts believe that the shotgun may have been the most deadly. The shotgun Holmes used fires twelve projectiles with every shot. Many shotguns can fire five rounds before needing to be reloaded, a total of 60 projectiles, each capable of killing a human being.

Due to its lightweight and compact frame, the Glock 9mm is one of the most popular firearm options for law enforcement officials.

A Glock 10mm, a similar weapon to the one pictured here, was recovered at the scene of the Sandy Hook Elementary School shooting in Newtown, Conn. The gun was purchased legally by shooter Adam Lanza's mother.

Glocks, and all handguns, are currently considered "regulated" firearms in Maryland, meaning a purchaser must pass a state background check.

The Glock was originally developed for the Austrian Army in 1982, but quickly became popular with gun enthusiasts worldwide. The extensive use of synthetic materials in Glocks made them relatively light and affordable, compared to other gun models at the time.