I did some measuring on some 8 mag cases.
Measuring to the shoulder I show: unfired 2.449
fired 2.478
OAL: unfired 2.841
fired 2.844
Is it normal to have the shoulder blow out this much?
If your shoulders are blowing out that far then it sounds like your dies are setup wrong and overworking your brass by pushing the shoulder back too far.
If you are FL sizing and you set the dies up per the instructions then you are probably overworking your brass. A belted mag should be sized off the shoulders just like a nonbelted case.
The comparison was between a new unfired case and one that had been fired. I will have to measure a sized case to see how far I am setting the shoulder back.
I have noticed this with Federal and Winchester brass in 7 rem mag, and with Remington brass in 8 rem mag. I had some once fired brass from an old rifle that I made the mistake of full length sizing once for a new rifle. Brass made it about 2 more loads before showing signs of case head separation. Now I just shoulder bump all brass to about 0.002 less than my rifles chamber size.
