Winchester Large Pistol Primers Failing

[RudyVey]

Update: from the last box of LP I used (the one marked March 2017) I just had three rounds out of 200 fail. Guess its is the primers.....the other boxes (from the same delivery I guess) had no problems and I never experienced any with SP and have used thousands of them. One of the three rounds finally fired after the third attempt, but two did not at all. Too bad I tossed them in the box at our range for bad ammo, should have taken them home and open them up and analyze.

[Dranoel]

Just curious...  What did the anvil look like in the failed primers? Was it pushed in flush with the cup? Or did it stick up a bit from the cup?

I had an issue many years ago very similar with Remington primers. Turned out they were a thousandths shorter (back to front) than the CCIs I had used before and the anvil was not seating in the cup all the way. A minor adjustment to my primer tool to press them a hair deeper cured the problem.