I read the entire post on TOS and cannot help but suspect something else is going on with the rifle. I personally wouldn't pair a new bolt with a used extension/barrel unless I had to. Wear starts with the first round fired. I could care less if the Relia-Bolt works or not because I would never buy one but I do believe it deserves a chance to prove itself. Two broken bolts in two different guns would suggest a pattern. Two broken bolts in the same gun does NOT.