A expansion chamber assembly for a firearm is disclosed. The expansion chamber contains an outer tube containing a front end and a rear end, a front cap coupled with the outer tube at the front end, a rear cap coupled with the outer tube at the rear end, an inner tube retained within the outer tube by the front cap and the rear cap, wherein the inner cap contains one or more through apertures to allow expanding gasses to move from the inner tube into the outer tube, and one or more exit apertures to allow expensing gases to exit the expansion chamber assembly.