I had the same problem with my new Weatherby Mk V. there were some loads it just would not set off. I got nice, deep indentations in the primers, but they didn't go boom. I first took it to a "gunsmith" and asked him ti disassemble the bolt and make sure it wasn't clogged with grease or whatever, and he didi, and still didn't work. He asked me why I was using .280 cartridges in a 30-06, and I told him it was because I could. He didn't understand reloading. I sent the rifle back to Weatherby and told them that it wouldn't work right, they adjusted something ( I can never read the repair order) and now it's fine.