MERCURY has been meticulously engineered for the .223 "" 5.56 caliber to provide superior recoil reduction and neutralize muzzle rise with a smooth"" balanced release of blast energy. Progressive 90 side ports vent combusting gases at intervals that spread out the recoil impulse for efficient"" accurate follow-up shots. Like all Ultradyne muzzle devices"" a timing nut is included for easy installation.