M3 submachine gunThe M3 is an American .45-caliber submachine gun adopted by the U.S. Army on 12 December 1942, as the United States Submachine Gun, Cal. .45, M3. The M3 was chambered for the same .45 ACP round fired by the Thompson submachine gun, but was cheaper to mass produce and lighter, at the expense of accuracy. The M3 was commonly referred to as the "Grease Gun" or simply "the Greaser," owing to its visual similarity to the mechanic's tool. The M3 was intended as a replacement for the Thompson, and began to enter frontline service in mid-1944.
Pistol gripOn a firearm or other tools, a pistol grip is a distinctly protruded handle underneath the main mechanism, to be held by the user's hand at a more vertical (and thus more ergonomic) angle, similar to the how one would hold a conventional pistol. In firearms, the pistol grip is located behind the trigger and generally held by the hand that operates the trigger. Rifles and shotguns without pistol grips are generally referred to as having "straight" or "upland" (shotguns only) style stocks.
Selective fireSelective fire, or select fire, is the capability of a weapon to be adjusted to fire in semi-automatic, fully automatic, and/or burst mode. The modes are chosen by means of a selector switch, which varies depending on the weapon's design. Some selective-fire weapons have burst fire mechanisms to limit the maximum number of shots fired automatically in this mode. The most common limits are two or three rounds per trigger pull. Fully automatic fire refers to the ability for a weapon to fire continuously until either the feeding mechanism is emptied or the trigger is released.
FireteamA fireteam or fire team is a small modern military subordinated element of infantry designed to optimize "NCO initiative", "combined arms", "bounding overwatch" and "fire and movement" tactical doctrine in combat. Depending on mission requirements, a typical "standard" fireteam consists of four or fewer members: an automatic rifleman, a grenadier, a rifleman, and a designated fireteam leader. The role of each fireteam leader is to ensure that the fireteam operates as a cohesive unit.