OP - Take a moment and visually compare the brass you are trying to size with the virgin brass you mentioned. If there is no huge obvious difference, I would guess that your rifle has a large chamber and your fired brass has stretched. So perhaps you are just experiencing a tougher-than-normal sizing job. Lube your brass well. Back your sizing die out of the press a whole turn or even more. Attempt to size the brass. If it goes, turn die in half a thread at at time, running the brass in each time. Report on what you find when trying this....Oh gosh no, definitely lubed.
I'm at a bit of a loss here, it sucks when all I want to do as a newbie reloader is reload, and I keep forgetting all these little bits and bobs, shellholders, case trimmers, this that and now this. Ugh.
I'm thinking i'll just grab another set of dies and see if it's that. quick 100$ check :/




















































