Bolt assembly from a rifle.
A bolt blocks the rear part of a gun chamber while the propellant is actively burning, forcing the expanding gases to push the projectile forward. Once the projectile has been fired, the bolt can be moved back to allow for a new cartridge to be inserted into the chamber. Automatic or semi-automatic firearms have bolts that operate automatically; when the gun is fired, the expanding gases push the bolt back. A recoil spring forces the bolt forward again, grabbing a fresh cartridge in the process, while the old casing is kicked out. In rifles and shotguns, bolts need to be operated manually. There are three types of manually-operated bolts: bolt action (often found in rifles), lever action (popular in hunting rifles), and pump action (found in shotguns).
Can be obtained after dismantling any firearm.
- Likely scavenging locations: