Chamber (firearms)

The chamber of a firearm is the cavity at the back end of a breechloading weapon's barrel or cylinder, where the ammunition is inserted before being fired.

[2] In the barrel chamber, fluting refers to gas relief flutes/grooves used to ease the extraction of cartridges.

Roller or lever-delayed blowback arms require that the bolt starts moving while the bullet is still in the barrel and the spent case is fully pressurized.

Using traditionally cut (non-fluted) chambers in the StG 45(M) resulted in separated cartridge case heads during testing.

[13] Ballistics identification has also seen the development of microstamping technology which purposefully creates chamber marks through engravings on the firing pin and breech face.