Just started reloading for my M1a National match, and have a question about flattened primers. I am running Hornady 168 gr HPBTs over 39.5 gr H4895, Winchester WLR primers, in LC 11 cases.Cases were once fired military brass, they had to be sized twice to fit in my cartridge gauge (won't go there again). Cases were trimmed, primer crimps removed, and necks de burred, bullets seated to a COAL of 2.8 in. Accuracy was awesome considering I am still learning the rifle (.6 inch at 100 yards scoped), but every case showed flat primers, nothing had extruded into the firing pin hole, and there were no other signs of over pressure. Any advice on how to eliminate flat primers? do I need to worry about this? Thanks in advance for reading this.