I've been reloading .303 Brit for about two years now and have done probably a few thousand rounds, trying to neck size only, tough with 11 rifles here that shoot 303 and only 350 cases in hand. I had my first case head seperation on Sunday, in a MkIII Ross. The brass showed no signs of seperation before firing, had been FL sized once and neck sized once. When I last loaded them they only took a trim of a few thou. I've culled all of this loaded ammo with cases from that manufacturer that I have and will pull them down. How can I check inside the case for signs of thinning, only by sectioning?

Sorry for the hijack, thought the question was relevant with all the other info given here