this is why factory ammo, that is almost always under size, does not fail with 1 firing. But the brass is already damaged on that 1 firing.
well here is a question. Can a case be stretched by using a full size die on it?
reason I am asking is this. As I stated in my previous post I initially set the head space using a piece of Hornady factory loaded ammo which as you stated is a bit on the short side. After that I have only neck sized them using a Forster BR neck sizer which I have set for a very loose bullet fit. On occasion a bullet will be a bit too loose so I keep a Lee full case resizer with the decapping pin broke off near the bench and just dump the powder into a pan and resize the case using the Lee die and then continue to load it. reason I am asking is that sometime 1 or 2 out of 50 of the reloads I would feel a moderate resistance when closing the bolt and wondered if I could have been setting that shoulder back in the process with the chamber and head space being set too tight.