Abstract: An ammunition cartridge may include a cartridge body including a substantially straight sidewall defining a cartridge cavity. The ammunition cartridge may also include a cartridge base and a primer received within the cartridge base and projecting at least partially into the cartridge cavity. The ammunition cartridge may also include a propellant received in the cartridge cavity, and a sabot at least partially received in the cartridge cavity and including a sabot body having at least one sabot sidewall portion extending from a base portion to a sabot end defining an open-ended sabot cavity. The ammunition cartridge may also include a projectile at least partially received in the sabot cavity, and the projectile may include a front end defining a tip, wherein the sabot end extends beyond the tip and is configured to contact a preceding ammunition cartridge of a magazine without contacting a primer of the preceding ammunition cartridge.

Abstract: A biasing member for a bolt assembly of a firearm is described herein. The biasing member comprises a body having a first portion configured to engage and seat within a biasing member receiving indentation of an arm of the extractor, and a second portion configured to engage and seat within a receiving area along a bolt of the firearm. The body provides a biasing force directed against the extractor arm. The body comprises an elastomeric material, and is configured such that the first and second portions provide varying levels of compression sufficient to maintain a substantially constant extractor tension between the extractor arm and a cartridge.