Pressure discriminating cartridge chamber

Provided is a firearm cartridge chamber with a relief feature that traps a portion of a cartridge case within the cartridge chamber when fired. The relief feature causes the cartridge case to deform within the chamber, wherein it optionally separates into a forward section and a rearward section. The deformed case remains trapped after firing, preventing extraction of the fired case and the chambering or firing of any subsequent cartridges, thereby causing a firearm malfunction. The cartridge chamber can distinguish between higher and lower pressure cartridges by allowing for normal firing and function with blank training ammunition while also facilitating localized deformation of the cartridge case when firing standard ammunition that includes one or more projectiles. The inventive chamber prevents more than one higher pressure round from firing while allowing lower pressure or training rounds to fire without limitation, which aids in enhanced safety during training exercises.