Introduced in the 1930s by Federal Laboratories Inc., of Pennsylvania, the FRG became the standard riot gun used by the British Army throughout The Troubles in Northern Ireland.

A single-shot weapon, which breaks open by unlocking a catch at the top, it has since been replaced in British use by the multiple-shot ARWEN 37 revolver.

Spare parts could not be purchased, due to the 1977 arms embargo, so a domestically produced weapon, the "Stopper" replaced the Federal Riot Gun.

Fired at a relatively low velocity, the baton rounds are intended to knock rioters down, or momentarily stun them, but not to cause serious injury or death.

Safe operating procedures in the British Army eventually ruled out firing the gun directly at rioters, as it was found that the rounds could cause serious and permanent injuries.