SWS barrel nut is a timed barrel nut. If you can’t achieve proper torque and timing you
will need to add a shim. When adding shims only use one shim, using more than one
could result in false torque readings. Tighten barrel nut to 40-80 ft-lbs. We recommend
cycling the nut back and forth to “seat” the threads to get an accurate torque. Apply a
small amount of lubricant (gun oil or grease) to the threads prior to installation.