If I had the problem and did not had a friend to help me. I would order three sets of locking bolts( T/C makes them in several increments 1x,2x, and 3x). Generally barrels are shipped with 1x size, but you don't know what you have for sure. Also, do a webb search for locking bolt sizing. The webb has a better description than I could give using an inked felt tip pen blacken the locking bolt and using a diamond EZE Lap to work down the locking bolt to fit. Don,t use a dremel tool to remove the lug metal. Care must be taken to keep the top surfaces of the locking bolts flat and at the same angle as original. Best that I can do under present rules. The way that I have seen this problem solved is Ed changed the locking bolts until he found a set that worked.