I'm having some trouble with some Federal Gold Medal .223 brass. I'm getting major leakage around the primer pockets on a few cases. These cases originally had crimped primers, and I removed the crimp with a Lyman reamer. On the first firing, about 20% are showing leakage around the primer. Other brands of cases aren't doing this, despite being processed with the same tools. My regular Federal brass has been problem free. Any suggestions?