My Winchester safari express 375 has been failing to fire way more than a comfortable amount lately, and I have some questions. I roll my own ammo and CCI 250 and Remington large rifle magnum primers have both failed,I feel that eliminated the primers being the problem but I suppose it still could be. The FTF problem has happened with Norma Winchester and PPU brass. I’ve never had a FTF with my A square or Remington brass. Could it be the brass? Could the primer pockets be too deep and causing a high primer? I clean the primer pockets ever loading Sometimes a second strike will ignite it and sometimes it won’t. I have a hard time believing three different lots of brass to have the same problem. I seat the primers in the exact same manner every time. The only common variable is the rifle. It’s happened since it was new and I keep it clean. I’ve ordered a new firing pin spring, and the pin seems to come through the bolt far enough. Also the brass isn’t stretching bad so I’m assuming the headspace is ok. Thanks for the help!