Letter R

The Definition of Rim

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Rim

The edge on the base of a cartridge case which stops the progress of the case into the chamber.


19 Other Firearms Definitions You Need To Know


Double-Base Powder

A rapidly burning powder made by absorbing nitroglycerine into nitrocellulose (guncotton).

Knurled Surface

A metal surface which contains a pattern of ridges or beads.

Gain Twist

A form of rifling where the helical angle (pitch) sharpens progressively down the bore in the interest of maximizing the bullets ultimate rotational speed by initiating it slowly.

Hang Fire

An unexpected delay between the triggering of a firearm and the ignition of the propellant. This failure was common in firearm actions that relied on open primer pans, due to the poor or inconsistent quality of the powder. Modern weapons are susceptible, particularly if the ammunition has been stored in an environment outside of the design specifications. Reloaded ammunition may also be the cause if not reloaded properly

Bore

The tunnel down the barrel of a firearm through which the projectiles travel.

  • A smooth-bore firearm is one that does not have rifling on the barrel's internal surface.
  • A big-bore firearm is one that fires a large caliber.
  • A small-bore firearm is one that fires a small caliber.

Express Sights

"V" shaped rear leaf sights mounted to a rifle barrel on a block or on a quarter-rib, sometimes solid standing, sometimes folding, and often mounted in a row of similar leaves, each of a slightly different height, marked with the range for which each is regulated

Flinch

To jerk a firearm off target inadvertently in the instant of firing in timid anticipation of recoil. Commonly caused by learning to shoot with a gun more powerful then they are ready for.

Grip Safety

A passive, external safety typically located on the backstrap, which must be fully depressed to release the trigger. Most 1911-pattern pistols feature a grip safety.

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.

Dust Cover

A small hinged or sliding door covering the ejection port of a firearm to prevent detritus from clogging the works.

Pitch

The angle of the butt of a gun in relation to the line of sight. Pitch is measured by resting the gun with its butt flat on a floor, the top of the receiver against a wall and its muzzle pointing up. The distance of the muzzle from the wall is the gun's pitch down.

Comb

The top of a gun's stock, where a shooter rests his cheek when mounting a gun. As it is the top of the stock that determines the position of one's eye, and one's eye is the rear sight on a shotgun, the position of the comb is very important in determining the proper fit of a shotgun.

Crosshairs

The cross-shaped object seen in the center of a firearm scope. Its more-proper name is reticle.

Long Gun

Another term for rifle.

Musketoon

A musket shortened for cavalry use.

Casket Magazine

A quad stack box magazine.

Bullet

The single projectile expelled from a gun. It is not the same as a cartridge, the cartridge is complete package, which includes the case, primer, powder, and bullet, which is called or a round. Bullets can be of many materials, shapes, weights and constructions such as solid lead, lead with a jacket of harder metal, round-nosed, flat-nosed, hollow-pointed, etc.

Firearm

A firearm is a portable gun (pistol or rifle), being a barreled weapon that launches one or more projectiles often driven by the action of an explosive force.

Duelling Pistols

Single shot pistols, of a design originating in England, in vogue circa 1770 - 1850, built necessarily in pairs, either of flintlock or percussion ignition, usually finely made and cased together with loading accessories. Dueling pistols tended to be lighter and sleeker than their contemporary service pistols. They tended to have smoothbore (or sometimes secret, scratch-rifling), octagon (or octagon-to-round) barrels around nine or ten inches long of some form of damascus steel, bores just over a half-inch, ramrods, rudimentary sights front and rear, single-set triggers, roller-bearing frizzens and curved grips integral with full or half-stocks. They were usually of high quality construction, sometimes with silver furniture, but normally of relatively plain decoration.