For locking 2" diameter bulk and sausage gun barrels (DL-45, DL-59, etc.) into position against the back cap to prevent loosening during barrel rotation.
For proper adjustment:
1. Thread barrel all the way into the base of the back cap
2. Back the barrel out 1/2 turn
3. Tighten the lock ring against the back cap to preserve this position and enable smooth barrel rotation during caulking.