Abstract: A small arms silencer utilizes a transversely perforated biased piston mer, moving in a vented, perforated, housing, to temporarily contain projectile blast gases in a sealed-off area. The trapped noise producing blast gases are released through a valve in the housing at a rate and frequency which makes the blast noise level inaudible. Barrel movement compensation is provided by a combination of an impulse of gases acting against a closed end of the housing in opposition to a counter force generated by the moving piston on the other end of the housing.