A revolver is a repeating handgun that has at least one barrel and uses a revolving cylinder containing multiple chambers (each holding a single cartridge) for firing.
pistol is a weapon originally designed, made, and intended to fire a projectile (bullet) from one or more barrels when held in one hand.
The MSBS GROT is a selective fire modular assault rifle which is capable of semi-automatic, 3-round burst and fully automatic fire.