Fired brass hardens and will need to be sized slightly more due to setback than virgin brass. So when setting up an FL die to size brass fired in a larger chamber to fit a tighter chamber, you need to make sure you're fully sizing the brass, not partial fl sizing. Even then occasionally you'll get fl brass that just doesn't size down enough to fit.
Just buy virgin brass and have dedicated brass for the tight chambered gun. No risk of accidentally having a round that won't chamber at the wrong time, like on a hunt.
Brass was once fired Hornady and annealed after first firing. I do NOT FL size any rifle brass at all unless it's going to be used in an AR or other semi-auto.
I think I probably was just a little too conservative in the way I set up my FL die. It will be corrected with about a 0.002" increase in shoulder bump. My body die will get proper attention too.
