Hello all ! I just found this forum and I like what I see so far.
I started loading for my 300 WSM using my once-fired Fusion brass. I had the same problem with loose primer pockets. Some primers just fell out on the first reload. I would recommend buying some higher quallity brass. I bought some new Winchester brass and had to do a lot of sorting by weight, due to a large variance from case to case. I'll be buying Norma brass next time. I got a little obsessed with accuracy on this one, and do a lot of match prep stuff, minus neck-turning. I trim after every firing, just to be safe, and set my full-length sizer die a little short, where it just bumps the shoulder. They are a little snug, but not enough to make chambering difficult.