JK Armament HD Minimalist Muzzle Device .30/.45 Caliber 5/8x24 Nitrided Black. This nitrided 17-4 stainless steel muzzle device weighs just 2.2 ounces and is a scant 1.0 inch long. It provides secure rapid attachment and removal of your JK 155 suppressors and any other suppressor with an ASR-compatible mount such as one of our Taper Mounts. Specifications for JK Armament HD Minimalist Muzzle Device: Manufacturer: JK Armament Fabric/Material: 17-4 Stainless Steel Color: Black Finish: Nitrided Threads per Inch: 5/8x24 Weight: 2.2 oz Projectile Caliber: .45 Caliber .30 Caliber Package Contents: JK Armament HD Minimalist Muzzle Device JK Armament JKMDMDM24: HD Minimalist Muzzle Device .30/.45 Caliber 5/8x24 Nitrided Black