Ruger 90590: Ruger's Precision Hybrid Muzzle Break Reduces recoil by as much as 58 percent and improves accuracy over a longer string of fire. The brake locks into position using an easy-to-use external jam nut. This muzzle break installs quickly using a 7/8" box wrench or crescent wrench, and is manufactured from alloy steel with a matte black finish.