I am getting the best results that I have had in some time, shooting a well worn barrel with threads so loose that when I screwed it on, I felt the need to remeasure and figure out how much engagement I had sacrificed. This was a barrel that was given to me, chambered for a panda. My early Viper has threads that are a few thousandths too small for the barrel. I bought an adjustable die and got in a little to big of a hurry setting it for my last cut. It makes me want to do a before and after test with one of my other barrels, that were fitted to my action. Seriously, I have heard more than one undersized, shot well story. I have no idea why. On the other hand, the fit may have nothing to do with how well the barrel shoots. If I were fitting barrels on a lathe, I would be tempted to make nuts for all the common tenon dimensions, to check threads with. In this particular situation, one of the issues that I ran into was that even though I had the over the wires measurement slightly smaller than a barrel that fit, cutting the threads down with my die left the threads sharp, and I my action's insert was thread milled, and I doubt that the bottoms of the Vs come to a point, so I had to go a little smaller because of that. This put me into a range where the die setting was controlled by the thumbscrews that held it in the stock. Instead of being smart enough to measure from the top of the thumbscrew, to the other side of the stock, I guessed. The chamber is an oddball as well, and on the first day that I tried it at the range, the only die that would make the cases fit in the seater reduced the shoulder diameters about .0075, which did not seem to matter at all as far as the groups were concerned. There goes another theory. Later I switched sizing dies, and seaters, and it still shoots very well, but if I run out of long shanked bullets, I may be in trouble.
