Tilting bolt

Tilting bolt action is a type of locking mechanism in self-loading firearms. Essentially, the design consists of a moving bolt driven by a piston with gas pressure from the gas port behind the muzzle. The bolt drops down into receiver recess and locks on bolt closing. Tilting the bolt up and down locks-unlocks in the breech. This tilting allows gas pressure in the barrel from firing the gun to lower to safe levels before the cartridge case is ejected. This is in contrast with rotating-bolt mechanism of almost all modern repeating rifles. For handgun design; tilting barrel is very popular with Browning style operating mechanism. The tilting bolt has lost favor in contemporary firearm design of rifle caliber to locking systems such as the rotating bolt due to reasons such as increased wearing of the surfaces acted on & better potential accuracy of rotating bolt. Yet it is widespread in vintage firearms listed below.