The odds of a primer disintegrating with no shards are essentially nil. I think something else has happened: most likely you blew a primer which fell out of the case during extraction/ejection. You should pull the barreled action out of the stock, remove the sheet metal, and make absolutely certain that SOB is not rattling around up where the locking lugs go when the bolt is closed. I had that happen one time and I [bleep] up the rifle. I didn't realize I'd blown the primer out of the case, it smelled smoky and I thought I'd just popped one, so I cycled the action, loaded a new shell into the chamber .. the action closed fine, the primer rolled from wherever it was hiding and dropped in behind a locking lug .. I was unable to eject the chambered shell .. busted the bolt handle off trying. You don't want to do that.
Tom
