Re: Developing a new load, a few questions
You can get a flat primer and a funny looking bolt face from over doing it on the size die.
When you fire an over-sized case if slams into the bolt face flattening the primer and making odd marks on the cartridge head.
If I were a betting man I would look there for your "pressure problems."
You should also check for potential case head separation.
RL-22 and H-1000 give me 2970 and 2900fps respectively with the 200gr Accubond.
Both powders are a bit better choices for accuracy at top velocity.