Yankee Hill Machine Victra 12 Beretta Optima HP Shotgun Supressor Mount. Ours thread into the end of your shotgun's barrel using the standard choke threads to secure the suppressor to the shotgun but it does not provide any choke or constriction to the shot load. That job is handled by our unique choke cone which is located in the front cap of the V-12 suppressor itself. Specifications for Yankee Hill Machine Victra 12 Shotgun Supressor Mount: Manufacturer: Yankee Hill Machine Fabric/Material: 17-4 Stainless Steel Color: Black Finish: Melonite Diameter: 1.2 in Package Contents: Yankee Hill Machine Victra 12 Shotgun Supressor Mount YHM V-12 Jam Nut (YHM-1250) Yankee Hill Machine 1255A: Victra 12 Beretta Optima HP Shotgun Supressor Mount