Letter J

The Definition of Jam

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Jam

A malfunction which locks up the gun so badly that tools are required in order to fix it. Sometimes used to denote a simple malfunction, but many people make a distinction between a complete jam and a simple malfunction.


19 Other Firearms Definitions You Need To Know


Stance

How the shooter positions her body while shooting. The three most widely used handgun stances are Weaver, Isosceles and Chapman stance.

Tracer

A type of ammunition that utilizes a projectile or projectiles that contain a compound in its base that burns during its flight to provide a visual reference of the projectile's trajectory.

Pattern

A shotgun term which refers to the manner in which the pellets spread out as they exit the gun. "The pattern" refers to the overall shape of the entire set. A tight pattern is one in which the pellets are closely grouped when they land on target. A loose pattern is one in which the pellets are widely spread.

Mouse Gun

A name for any palm sized handgun which fires a small caliber.

Gloaming Sight

A second, folding or pop-up front sight bead of larger than usual size, perhaps not as accurate as a normal fine bead, but easier to see in the gloaming (twilight) or dawn.

Timing

The proper adjustment of the various interrelated moving parts of a gun so that every operation works in proper sequence, such as that the two ejectors of a double gun kick out the spent cases at the same instant and with the same force.

External Safety

A safety lever or button found on the outer surfaces of the firearm and is accessible to the user. Enabling the external safety should prevent accidental pulling of the trigger. However, the best safety is always you.

Sporting Firearm

Any gun that can be used in a sport.

Cut-Away

A firearm that has had numerous careful machining cuts taken in its exterior with a view to exposing and demonstrating the functioning of critical parts of its mechanism

Biathlon

A shooting sport that combines both skiing and rifle shooting. It is the only shooting activity in the Winter Olympics. There is also a summer biathlon which involves running and shooting but it is not yet an Olympic event.

Snap Shot

A quick shot taken without deliberate aim.

Saddle Ring

A steel ring, around an inch in diameter, mounted to a stud, usually on the left side of the receiver of a carbine, to which may be tied a leather thong to secure it to a saddle or a scabbard so as not to lose the carbine when riding a rambunctious horse.

Model 70 Type Safety

A small lever mounted to the cocking piece of a Winchester Model 70 rifle, rotating on a vertical axis from front (Fire), halfway back (Safe, but allowing bolt movement), and fully back (Bolt and firing pin locked Safe). While, like the Mauser, commendable for locking the firing pin instead of just the trigger, its fore and aft movement is both easier to operate and it allows lower mounting of telescopic sights, reducing parallax between the line of sight and the line of the bore and increasing the range of distances for which the scope may be reliably sighted-in.

Stock

The back part of a rifle or shotgun, excluding the receiver.

Center Hold

A sight picture of when the center of the target is half covered by the front sight when the sights are properly aligned. Also see six o'clock hold and cover hold.

Muzzle Control

Being aware of and responsible of which direction your firearm is pointed at all times, and always keeping it pointed in a safe direction.

Dud

A round of ammunition that does not fire.

COM

Abbreviation for Center Of Mass.

Minute Of Angle

A 1/60th part of a degree, the unit of measure used in adjusting rifle sights. As it turns out conveniently, a minute of angle translates almost exactly to one inch at 100 yards (actually 1.047 inches), to two inches at 200 yards and three inches at 300 yards