I bought some once fired 257 Rob brass a while back. When I inspected them a number of the primers were backed out .010-.015. Also when I PFL sized the cases they would not come anywhere close to fitting in my rifle and I had to bump the shoulder back about .010-.015. Do you think the rifle they had previously been fired in had excessive head space?
After being sized to fit my chamber they worked fine but will I see decreased brass life?

What's done is done.

Just neck size them from here out, and live with it.

I think you figured out your problem yourself.

"What caused this?"

Probably shot with a reduced load. The firing pin drives the case forward, there is not enough pressure to expand the case back to the bolt, but there is enough pressure to force the primer back against the bolt face. There might have been enough pressure to stretch the case to some extent.

You should watch out for case head separations. A bright ring, part way up the case where the thinner case walls begin, is the first warning sign.

Michael

Deals like this are where a $35 hornady head space measuring kit becomes really valuable. I could tell a number of stories about how its helped me analize once fired brass. Not to mention proper set up of my dies related to my own brass as it work hardens or I anneal.
It is definately worth every penny for even low volume reloaders.

+ 1

+ 1 minus whatever that modified case crap thing is. The inserts are handy.

Yes I use the head space gauges for die set up and measure for possiable too much headspacein a new chamber, No modified case I use the sinlair "nut" type compator and case fired from said chamber