For firearms, the pistol grip is generally used 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.
The pistol grip often serves multiple functions, such as a magazine housing or tool storage. In some firearms, like the Finnish light machine gun KK 62, the pistol grip is also used as a handle to charge the weapon.
Pistol grips are a defining feature in some states' gun laws in the U.S. Pistol grips which protruded below the weapon and not as a portion of a conventional rifle or shotgun stock are currently regulated in a few states and were regulated by the now-expired Federal Assault Weapons Ban.
The first rifle ever to use a pistol grip was the DELVIGNE PATENT rifle made by LESOINNE ET PIRLOT FILS, LIEGE in 1840.