FWIW - I had some primers a couple years ago blow 3 primers out of a box of 20 reloads. This was with a known good load I had been shooting in that rifle for years and well below book max. I sent them back with the sales rep that covered my FFL's shop and got a letter and a gift certificate from the manufacturer saying the primers were indeed defective in that lot. I'd agree with others here and back down on the powder first, but if it still happens it might not be the powder.
