Letter M Firearms Glossary

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M1911

The official US military designation for the Colt .45 semiautomatic pistol adopted by the US in 1911. The gun was designed by John Moses Browning, and produced by Colt. During trials, the Browning-Colt design beat out several competing designs, including one from Savage and a .45 caliber version of the German Parabellum ("Luger"). The M1911 saw its first combat in the Philippines and then in World War I. Early use showed that it could be improved and in 1921 the M1911A1 was introduced, which featured a few changes like a reocontoured frame, shorter trigger, and a rounded backstrap. The M1911A1 remained the standard US military handgun until it was replaced in the 1980's by the Beretta M9. However, it remains very popular with civilian shooters in the US, and has been modified extensively to update it to conform to more modern theories of handgun usage.

Machine Gun

A fully automatic firearm that rapidly fires multiple rifle-caliber shots with a single pull of the trigger.

Machine Pistol

A handgun-style fully automatic or burst-mode firearm.
A machine pistol is not the same thing as a Submachine Gun

Mag

Slang word for Magazine.

Magazine

A secure storage place for ammunition or explosives. On a firearm, it is the container, either fixed to a firearms's frame or detachable, which holds cartridges waiting to be fed into the gun's chamber.
Detachable magazines for the same gun may be offered by the gun's manufacturer or other manufacturers with various capacities. A gun with a five-shot detachable magazine, for instance, may be fitted with a magazine holding 10, 20, or 50 or more rounds.
Box magazines are most commonly located under the receiver with the cartridges stacked vertically.
Tube or tubular magazines run through the stock or under the barrel with the cartridges lying horizontally (like on a shotgun or lever action rifle.
Drum magazines hold their cartridges in a circular mode (for example the famous drum magazine on a Thompson submachine gun).
On a revolver, the magazine is known as the cylinder.
Internal magazines are built into the firearm and are not removable. Examples of internal magazines are the tube magazines of a shotgun or the magazine on a Mosin Nagant.
A magazine is not a clip!

Magazine Disconnect

Another term for Magazine Safety

Magazine Follower

Same as Follower. A plate, mounted to the top of a spring, inside a magazine, over which cartridges may slide smoothly as they are guided into the chamber of a repeating firearm.

Magazine Loader

A mechanical device to make it easier to fill magazines using less hand strength and without hurting one's fingertips or thumbs.

Magazine Pouch

Commonly shortened to mag pouch, this is a device to hold extra magazines which fastens to the shooter's belt.

Magazine Safety

A mechanism that prevents the gun from being able to fire when the magazine is removed from the gun, even if there is still a round in the chamber.

Magazine Well

The opening in the bottom of the gun into which a box magazine is fed. On a semi-auto handgun, the magazine well is at the base of the grip; on a rifle, it is usually placed in front of the trigger guard.

Magna

Smith & Wesson term for a revolver grip design introduced in the 1930s where the top of the grip extends higher than it had in earlier configurations, to provide a more comfortable hold.

Magnum

From the Latin for "more." A term indicating a relatively heavily loaded metallic cartridge or shotshell and a gun safely constructed to fire it. It generally indicates a round which cannot be interchanged with other loadings of the same caliber (for example, a .22 Magnum shell does not fit within a firearm designed to fire .22 Long Rifle ammunition).

Mainspring

A strong spring which activates the striker or hammer of a firearm.

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.

Malfunction

A misfeed or other failure to fire which can be cleared on the spot and without tools.

Manual Safety

A safety which the shooter must deliberately disengage in order to fire the gun. The most common form of safety mechanism is a switch that, when set to the "safe" position, prevents a pull of the trigger from firing the firearm.

Marksman

A person who can shoot up to the mechanical capability of their weapon.

Martini

A hammerless single shot action type whereby a breech-block, hinged at the upper rear, operated by an underlever, tilts downward to expose the chamber.

Match Grade

A higher quality item used to increase accuracy, generally used for competition in a match. Match grade ammo and barrels are the most common improvements made to a firearm to improve accuracy for competition.

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.

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.

Matchlock

An early system of ignition for muzzle-loading firearms where a priming charge is loaded into a flashpan with a separate, manually-operated cover. To fire, the cover is opened and then a slowly smoldering wick, held in the nose of the curved arm, is lowered by means of a lever (precursor to a trigger) to ignite a priming charge which then ignites the main propellant charge inside the barrel.

Matchlock

A black powder muzzleloading firearm action which relies upon a serpentine or S-shaped piece of metal to hold a smoldering match. By pressing the lower end of the serpentine, the upper end holding the burning match contacts the priming powder in the pan.

Mauser Action

The premier bolt action, whose design by Paul Mauser coalesced in 1898, and from which were derived the Springfield 1903, the Winchester Model 70 and many others.

Mauser Safety

A small lever mounted to the cocking piece of a Mauser 98 action (and its copies such as the Springfield 1903), rotating on a longitudinal axis from left (Fire), up to the top (Safe, but allowing bolt movement), and over to the right (Bolt and firing pin locked Safe). While commendable for locking the firing pin instead of just the trigger, its up-and-over arc of operation requires a scope to be mounted awkwardly high. Paul Mauser is not to be blamed; when his safety was developed, telescopic sights were in such infancy as not to be worthy of mainstream consideration.

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.

Metallic Cartridge

A cartridge with a metallic case. (Early cartridge cases were made of linen, paper, etc.)

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

Mirage

A tendency for layers of air of different temperatures near the warm ground to cause refraction in the line of sight and disturbance of the perceived point of aim.

Misfeed

Is a failure of the next round to completely enter the chamber. Misfeeds and failures to feed are very similar, a failure to feed is a round that never even leaves the top of the magazine, while a misfeed is a round that leaves the magazine but does not enter the chamber.

Misfire

The condition of a cartridge not firing when an attempt to fire it is made. It can be caused by either a defective cartridge or a defective firearm. The term is frequently misused to indicate a Negligent Discharge of a firearm.

Mississippi Rifle

Nickname for the U.S. M1841 Rifle, a .54 caliber muzzleloading rifle. The name comes from their use by a group of U.S. Volunteers from Mississippi who were commanded by Jefferson Davis in the Mexican War. Some were later rebored to .58 caliber.

MOA

Abbreviation for Minute Of Angle

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.

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.

Monoblock Barrels

A method of building a pair of barrels where the entire breech end of both barrels and the lumps together are machined from one solid piece of steel. The barrel tubes are then fitted separately into this monoblock and the ribs attached. Often identifiable by a distinctive ring around the barrels about three inches in front of the breech end. The favored jointing method of the Beretta company. An incorrect euphemism for sleeved barrels.

Monte Carlo Comb

The Monte Carlo comb came to rifles via shotgun stocks. It rises well above the ordinary comb line of the stock at the butt and tapers downward toward the point of the comb. This raised portion of the stock lifts the face of the shooter and his or her line of sight well above the standard elevation provided by the classic style. However, the same amount of drop is maintained at the buttstock. A shooter with a long neck who often has trouble getting his or her face down far enough on the comb of the regular stock benefits from the Monte Carlo style.

Monte Carlo Stock

A rifle or shotgun stock that has a Monte Carlo style comb

Moon Clip

A moon clip is a ring-shaped or star-shaped piece of metal designed to hold multiple cartridges together as a unit, for simultaneous insertion and extraction from a revolver cylinder. Unlike a speedloader, a moon clip remains in place during firing, and after firing, is used to extract the empty cartridge cases.

Mortar

An artillery piece used to fire shells over short ranges at very high trajectories.

Mouse Gun

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

Muffs

Slang for Ear Muffs.

Multi-Barreled

A gun with more than one barrel, the most common being the double-barreled shotgun.

Mushroomed Bullet

A description of a bullet whose forward diameter has expanded after penetration.

Musket

A Muzzleloading long gun which has a completely smooth bore and is intended to fire a single projectile rather than a collection of shot.

Musketoon

A musket shortened for cavalry use.

Muzzle

The open end of the barrel from which the projectile exits.

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.

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.

Muzzle Energy

The power of a projectile or a load of shot at the point that it exits the muzzle of a firearm, normally expressed in foot-pounds.

Muzzle Flash

A muzzle flash is the visible light of a muzzle blast, which expels high temperature, high pressure gases from the muzzle of a firearm. The blast and flash are caused by the combustion products of the gunpowder, and any remaining unburned powder, mixing with the ambient air. The size and shape of the muzzle flash is dependent on the type of ammunition being used and the individual characteristics of firearm and any devices attached to the muzzle (such as a muzzle brake or flash suppressor)

Muzzle Velocity

The speed of a projectile or a load of shot at the point that it exits the muzzle of a firearm, normally expressed feet per second.

Muzzleloader

The earliest type of gun, now also popular as modern-made replicas, in which blackpowder and projectile(s) are separately loaded in through the muzzle. The term is often applied to cap-and-ball revolvers where the loading is done not actually through the muzzle but through the open ends of the cylinder's chambers.