The XXX was designed specifically for todays 50 caliber precision rifles but works equally well on the CheyTac cartridges or the 416 Barrett. There are no crush washers, flat washers, or Loctite required. Simply you and a crescent wrench. These brakes need to be ordered caliber specific unless your gunsmith wants to open it up himself.19.6 oz.5.035" Long American Precision Arms APA Gen II XXX Bastard .50 1x14 TPI Brake