Letter E

The Definition of Eye Relief

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Eye Relief

The distance that equates the exit pupil size of a rifle scope's ocular lens to the entrance pupil of the user, in order to achieve the largest, unvignetted view. This distance must be sufficient to ensure that the ocular rim of the scope does not lacerate the shooter's eyebrow upon recoil. And, the scope should be positioned so that eye relief is suitable when the rifle is comfortably mounted.


19 Other Firearms Definitions You Need To Know


Hand-Detachable Locks

The firing mechanism of a break-open gun which may be removed for inspection or cleaning without the use of tools. The release latch may be plainly visible or concealed. A feature typically seen on sidelock guns but also on the Westley Richards "droplock" boxlock action.

Articulated Front Trigger

A spring-loaded hinged front trigger on a dual trigger side by side or over under shotgun, built to cushion its impact on one's trigger finger as the gun recoils when the rear trigger is pulled.

Colt

A firearms manufacturer started by Samuel Colt in 1855. Colt is most famous for the revolvers they invented and built in the 1800's and the semi-automatic pistol model 1911 designed by John Moses Browning, and for being the first manufacturer of the AR-15 type rifles.

Luger

American name for the German "Parabellum" semiautomatic pistol introduced in 1900. The Parabellum was designed by Georg Luger, and based on the earlier Borchardt pistol. The official German military nomenclature was "Pistole '08" or "Po8." At first, it was chambered for the 7.65mm Parabellum round. Soon, it was modified to use the 9mm Parabellum cartridge, which is what most people refer to today when talking about a 9mm cartridge. "Luger" is now a trademark owned by the Stoeger Arms Co.

Crane

A swing-out arm on a revolver, to which the cylinder is mounted when opened facilitates loading and cleaning.

Mag

Slang word for Magazine.

BATF

Short abbreviation for the Bureau of Alcohol, Tobacco, Firearms and Explosives

Thunder

With the execption of the BP model series, Thunder is the name of all of Bersa's pistols. The line currently consists of three frames.

• The Thunder .380 series, which is a very reliable and good looking compact blowback system .380 acp pistol (there is also a .22lr version).
• The full size Thunder Pro series (avalable in 9mm and .40 S&W) is a locked breech design.
• The Thunder Ultra Compact Pro series, locked breech, short recoil design which is more of a commander size Thunder Pro (available in 9mm, .40 S&W, and .45 acp).
The Bersa Thunders are well known among firearms enthusiasts for being extremely high quality guns at reasonable prices.

Under Barrel

The bottom barrel on an Over/Under shotgun.

Pellet (air gun)

Skirted projectiles used in pellet guns

Patch

A small piece of leather or cloth. A patch can refer to the wadding used in loading a muzzle loading firearms or the piece of cloth used to clean a firearm bore.

Trajectory

The arc described by a projectile (or a load of shot) after it exits the muzzle of a firearm. Falling objects accelerate downwards at a rate of 32 feet per second, per second. The faster a projectile travels, the greater the distance it can cover in a given time before dropping too far. Hence, the higher the velocity of a bullet, the flatter the trajectory it will achieve.

Thumb Safety

An external, manual safety which is typically disengaged with the firing-hand thumb.

Matched Pair

Two firearms that are manufactured identical in every way and are sequentially serial numbered and are sold as a set. The most common type of matched pair guns are cowboy style revolvers for a couple of reasons, both guns will feel exactly the same in the hands and they make the set more collectable.

Ejector Star

On a revolver, the collective ejector, manually operated through the center of an opened cylinder, when activated, clears all chambers at once.

Blank

A type of cartridge for a firearm that contains gunpowder but no bullet or shot. When fired, the blank makes a flash and an explosive sound (report). Blanks are often used for simulation (such as in historical reenactments, theatre and movie special effects), training, and for signaling (see starting pistol). Blank cartridges differ from dummy cartridges and snap caps, which are used for training or function testing firearms; these contain no primer or gunpowder, and are inert.

Spray and Pray

A term often used to refer to the very poor and dangerous practice of rapidly firing many shots at a target as possible in the hope that one or more may hit the target. This practice is a danger not only to bystanders but also to the shooter.

Lever Action

A type of firearm action which uses a lever located around the trigger guard area, (often including the trigger guard itself) to load fresh cartridges into the chamber of the barrel when the lever is worked.

BG

Abbreviation for 'Bad Guy'