Lightweight cartridge case and weapon system

A rifle system comprising:

• a high pressure ammunition round further comprising a cartridge case having
• a thin walled body region of uniform thickness extending to a base of the cartridge case,
• an opening at a mouth of the cartridge case for receiving a projectile,
• an outer surface wherein prior to firing of the ammunition round, the outer surface is substantially devoid of features configured for interfacing with a mechanical extractor, and
• the projectile which is partially inserted within the opening at the mouth and which comprises a front portion which protrudes beyond the cartridge case;
• and a rifle further comprising
• a barrel chamber wherein when the rifle is in a chambered state, an interior surface of the barrel chamber extends the length of the chambered cartridge case such that the entire chambered cartridge case is supported by the chamber;
• a bolt seated against a base of the chambered case for sealing the barrel chamber, the bolt travelling rearward in response to a firing of the chambered cartridge case;
• and
• a rear extraction mechanism for extracting a spent cartridge case through the rear of the barrel chambered in which a residual bore pressure remaining in the chamber after the firing of the chambered cartridge case holds the spent cartridge case against the rearward travelling bolt without the bolt inserting into a cavity of the spent cartridge case.