Headstamped "FC07" with TIGHT primer pockets. Is it military? No obvious sign of a crimp, but have to trim the pockets a good bit to get LP primers to seat. Picked them up at the range. Anyone have experience with them?
Are you sure there isn't a primer crimp? That's what usually makes primer seating difficult. It isn't always noticeable. Take a few and swage out the pockets and see what difference it makes.