Originally Posted by
bcp477
You mentioned o.312" a couple of times in your initial post.....but you never said what your final, wrapped bullet diameter was/ is. I assume that you meant that the bullet diameter, BEFORE patching, was 0.312". What is it after patching ? You mentioned an M48. As I am sure that you already know, the bore dia. of an M48 should be in the neighborhood of 0.314".....and the groove dia. should be around 0.323". Were you indicating, in your first post, that one of your Mausers has a bore dia. of 0.312".....and the other 0.001" less (or 0.311") ?
Just need some clarification - as a starting basis to make an attempt to figure out your problem. I also believe that we don't have details on your load (powder type and charge). The more precise data that we have to consider, the better the chance we can figure out your problem.
As it stands.....the problem could one (or more) of many factors : patched bullet too small, patched bullet too large, patch failure in the bore, too hot a load, too soft a bullet alloy(though I think you said the alloy was perhaps too hard- in your last post), etc. etc.