Letter M

The Definition of Modern Isosceles

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Modern Isosceles

In the Modern Isosceles stance, the feet are roughly shoulder width apart, with the gun-side foot closer to the target than the off-side foot. The knees are flexed, and the entire body leans slightly toward the target. The shoulders are closer to the target than the hips, and the hips are more forward than the knees. The shoulders are rotated forward and the head, rather than being upright, is vultured down behind the sights. The entire body thus has an aggressively forward appearance, and is poised to move quickly if necessary.


19 Other Firearms Definitions You Need To Know


Recoil Spring

The recoil spring is the powerful spring that cushions the slide in its rearward travel and then sends the slide forward again with enough force to drive the fresh round firmly into the chamber. The strength of the recoil spring is calibrated to run the slide without any outside assistance.

Extended Top Tang

A display of gunmaking skill with a possible benefit of strengthening the wrist of a heavily-recoiling rifle, whereby the top tang of the action is made extra long, shaped and inletted into the top of the buttstock, extending along the top of the wrist and up over the comb. Popularized by Holland & Holland and adopted by several of the finest contemporary riflemakers in the USA.

Holster

A gun holder that may be strapped to a human body, or affixed to the inside of a pack or bag, or dropped into a pocket. A holster serves to protect the gun's mechanisms and finish, to provide security by covering the trigger so it cannot be pulled inadvertently, and to present the grip of the gun at a constant angle for easy access. Some holsters also serve to obscure the outline of the gun so it may be more easily concealed. Typically made from leather or in plastic.

Open Bolt

A type of firearm in which the action is in the open position and the chamber empty prior to firing. When the trigger is pressed the bolt moves forward, chambering a cartridge and firing it and returning to the open position. When firing is stopped the bolt remains open and the chamber empty.

Three Rules

The NRA teaches the Three Basic Rules of Safe Gun Handling. There are additional rules, but these are the three that if any two are followed, nobody will be hurt. However, obviously, all three should always be followed.

Rule One: ALWAYS keep the gun pointed in a safe direction.
Rule Two: ALWAYS keep your finger off the trigger until ready to shoot.
Rule Three: ALWAYS keep the gun unloaded until ready to use.
The NRA established these three rules in 1871. They were created to be easy to understand and remember, ensuring the highest possible level of firearm safety.
See also The Four Rules

Keyhole

The tendency of a bullet to tip in flight and hit a target sideways, leaving a distinctly oblong hole. This destabilization of the spinning bullet in flight is typically caused by a bullet weight inappropriate for the rate of twist of the rifled barrel, an out-of-balance bullet or its having nicked an impediment such as a blade of grass, in flight.

Jump

The amount of change in the bore axis, measured both vertically and horizontally, while the projectile moves from the chamber to the muzzle when it is fired.

Lock

The firing mechanism of a a muzzle-loading weapon. In breech-loading firearms, the lock is the firing mechanism and breech-sealing assembly.

Obturation

The process of a bullet expanding under pressure to fit the bore of the firearm, or a cartridge case expanding under pressure to seal the chamber.

Pre-Travel

Some triggers can be pulled slightly backwards before the shooter can feel any tension and before the hammer or striker begins to retract. Pre-travel is any movement of the trigger that begins before the trigger starts to engage.

Mercury Recoil Compensator

A device fitted inside the buttstock of a heavily-recoiling gun or rifle, usually containing mercury and a valve. As the gun recoils, the mercury is displaced temporarily, increasing the duration, and thus diminishing the perceived impact of the recoil. The added half-pound of weight doesn't hurt either.

Recoil Crossbolt

A steel bolt, mounted transversely through a rifle stock just under and behind the front (and sometimes rear) receiver ring, sometimes concealed in the wood and usually against which the action is carefully bedded. When properly fitted, it helps distribute the recoil and reinforces stock at the point where wood has been removed to accept the action. Recoil crossbolts can be recognized by the flush-mounted circular steel fittings on the side of the stock, but are sometimes finished with contrasting wooden plugs and sometimes concealed completely. Also called Reinforcing Crossbolt.

Gas Vent

A passage built into a firearm to allow the safe conduct of unexpected gas, as from a pierced primer, to minimize damage both to the gun and to the shooter.

Annulus

A tiny circular recess at the base of a cartridge case surrounding the primer pocket. Recoil from fired cartridges invariably impress a discernable ring on the breech or bolt face of a firearm, providing some evidence of the amount of use it has seen.

Shooting Sports

There are a lot of different competitions and other games which involve firearms. These are all referred to collectively as the shooting sports.

Muzzle Brake

An attachment to or integral part of the barrel that redirects some of the pressurized gas that propelled the bullet out the muzzle to the sides and possibly rearwards from the direction of the bullet travel. This reduces the recoil of the firearm.

Riot Gun

A popular term for a short barreled repeating shotgun as frequently used in law enforcement and personal protection.

Stopping Power

A popular but imprecise term used to refer to the ability of a small arms cartridge to cause a human assailant or an animal to be immediately incapacitated when shot with it. A more precise term is be Wound Trauma Incapacitation (WTI).

Cover Garment

Any piece of clothing that covers the holstered gun. When the gun is worn on the belt, the most common types of cover garments are vests, sweaters, and jackets.