System for a multi-caliber self-loading action assembly

A self-regulating gas assembly for a firearm, the self-regulating gas assembly comprising:

• a gas block configured to interface with a gas port on a first end of a barrel of the firearm;
• and
• at least one piston having a piston face on a first end thereof, the first end located in the gas assembly with the piston face positioned to receive gas via at least one gas conduit from the gas port of the gas block;
• and
• a barrel extension positioned at a second end of the barrel opposite the first end;
• and
• a bolt carrier assembly including a bolt and a bolt carrier;
• wherein the barrel extension has a first slot and a second slot into which a lock lug of the bolt interfaces to engage the bolt into a first locked position and a second locked position, respectfully, wherein the firearm is configured to be discharged when the lock lug is in each of the first locked position and the second locked position, wherein the barrel extension engages a second end of the barrel opposite the first end;
• wherein the bolt carrier houses a second end of the piston at a second end opposite the first end;
• wherein the bolt includes the lock lug that slides within the barrel extension along a lock channel into/between the first locked position and the second locked position.