Upgraded replacement for factory piston is machined from hardened 17-4 PH stainless steel bar stock to stand up to the rigors of high-volume shooting without breakage. Tight dimensional tolerances and polished exterior help ensure smooth, reliable function of this critical part for consistent gas system operation and efficient cycling. Drop-in installation: simply remove the end cap and forearm, slip off the factory gas piston, and slip on the Ballistic Specialties piston in its place before reinstalling the forearm and cap. Separate models for 12 and 20 gauge.
SPECS: Stainless steel, natural finish. Fits Beretta 391 shotgun.
Catalog page 188