Letter T

The Definition of Throat Erosion

Arsenal Exchange - Firearms Classifieds - Industry Directory

Throat Erosion

The wearing of the portion of the barrel where the gas pressure and heat is highest as the projectile leaves the chamber. The greater the chamber pressure the more rapid throat erosion occurs which is compounded by rapid firing which heats and weakens the steel.


19 Other Firearms Definitions You Need To Know


Toplever

A lever on a break-open gun mounted to the top of the receiver which, when pushed with the thumb (normally) to the right, operates (usually) a Scott Spindle, which in turn withdraws (usually) a Purdey Underbolt from the bites in the lumps of the barrels, allowing them to hinge downwards and the gun to open.

Ramrod

A long, slender, dowel-like tool used to force powder and shot down the bore of a muzzle-loading firearm. For hand-fired guns, normally retained in some kind of receptacle attached to the gun's barrel. Carried separately for muzzle-loading cannon.

Falling Block

A type of action used primarily for single shot rifles whereby some kind of lever actuates a breechblock, moving it downwards in a vertical recess to expose the chamber. May have visible or enclosed hammer. For any given barrel length, it allows a shorter overall rifle length compared to a bolt action because no space is taken up by the forward-and-back cycling of the bolt. Most of the better British makers produced them in limited numbers around the turn of the last century, the Farquharson being the most iconic. Perhaps the best-known falling block action today is the Ruger No.1.

Extractors

A part in a firearm that serves to remove brass cases of fired ammunition after the ammunition has been fired. When the gun's action cycles, the extractor lifts or removes the spent brass casing from the firing chamber.

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.

Zero

A firearm is said to be "zeroed in" when its sights have been adjusted so that the bullet will hit the center of the target when the sights are properly aligned upon the center of the target. The farthest distance from a firearm at which the bullet's path and the point of aim coincide. This term is also used to mean the process of insuring that the sights of a firearm are properly aligned so that where they indicate the bullet will strike is in fact where it strikes.

Makarov

The Soviet Union's standard military and police side arm from 1951 to 1991 replacing the Tokarev TT-33 semi-automatic pistol and the Nagant M1895 revolver. Designed by Nikolay Fyodorovich Makarov, it is a blowback operated semiautomatic pistol which fires the 9x18mm Makarov cartridge, and holds 8 rounds in the magazine.

Rear Sight

The rear sight is placed at the end of the barrel nearest the shooter. It may be in the shape of a square notch, a U, a V, a ring, or simply two dots designed to be visually placed on either side of the front sight while shooting.

Double Triggers

On guns (mainly shotguns) that have two barrels, there is a trigger for each barrel that work independently from each other.

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.

Die

A piece of tooling used to form a sequence of uniform parts through the use of heat and/or pressure; especially, in firearms terminology used to form brass cartridge cases accurately to their correct size for reloading.

Live Fire Exercise

Any exercise in which a realistic scenario for the use of specific equipment is simulated. In the popular lexicon this is applied primarily to tests of weapons or weapon systems that are associated with the various branches of a nation's armed forces, although the term can be applied to the civilian arena as well.

Speedloader

A device used to reduce the time and/or effort needed to reload a firearm's magazine.

DAO

Abbreviation for Double Action Only. Is a type of firearm in which the firing mechanism cannot be cocked in a single-action stage. Firing always occurs as a double-action sequence where pulling the trigger both cocks and then fires the gun.

Jaws

The vise-like device on a flintlock hammer used to hold the flint.

Button Rifling

Rifling that is formed by pulling a die made with reverse image of the rifling (the 'button') down the pre-drilled bore of a firearm barrel.

DST

Abbreviation for Double-Set Trigger

Sleeved Barrels

An economical method of bringing new life to a damaged pair of barrels, regardless of their original method of jointing. The ribs are removed. The barrels are cut off 3" - 4" from the breech end and discarded. The bores of the remaining breech-end are reamed out oversize. New tubes are fitted down into the original breech section and filed down to fit flush. The original ribs are then replaced. Sleeving is considerably less expensive than building a completely new set of barrels. Much of the time required to build a set of barrels is concentrated in the fitting of the breech end to the receiver; this work is salvaged through sleeving. Sleeving can be recognized by a pair of circumferential lines around the barrels a few inches from the breech; the more invisible, the finer the job. A sleeved gun should always be identified as such amongst the proof marks, and if done in England must be properly reproofed. Photo Sleeving is not the same thing as Monoblocking.