The correct terms are barrel bolts, parts 23R and 23L if you order them from T/C. They are cheap and there is no good reason to be using a one-piece bolt these days. What others have failed to suggest is to replace the spring too! The new spring will push the bolts deeper into the frame for better lockup. And remember, DO NOT lubricate the bolts, run them dry!!! Here is what T/C says in their Owners Manual: "Never use any oils or grease on any internal parts." A lot of action problems can be traced to the use of oil on the bolts and other internal parts. Don't do it! :evil:
The correct-sized drift is necessary, and it is also a good idea to clamp the barrel lug in a vice. This way you have better control of the drift and hammer, and you can better catch the bolts, roller and spring when they all come flying out..... :-D