Firearm Glossary

forward assist: A button, found commonly on M16 and AR-15-styled rifles, usually located near the bolt closure, that when hit, pushes the bolt carrier forward, ensuring that the bolt is locked.

fouling: The accumulation of unwanted material on solid surfaces. The fouling material can consist of either powder, lubrication residue, or bullet material such as lead or copper.

frangible: A bullet that is designed to disintegrate into tiny particles upon impact to minimize their penetration for reasons of range safety, to limit environmental impact, or to limit the danger behind the intended target. Examples are the Glaser Safety Slug and the breaching round.