Problem with Winchester primers???

[Walkalong]

I bought 10,000 WLR primers when we had that "primer shortage" about 10 years back and am still shooting through them with ZERO misfires.

I bought quite a few right before it and still have some of them. They all go bang.

 

[ar10]

Found the problem

That is just about the perfect empirical evidence of a weak FP spring. Weak springs will cause inconsistent ignition. Some will fire, some won't. The fact that more fire than don't isn't at all surprising.

The other, even more common cause of inconsistent ignition is seating depth as many have said, and you have addressed. However, without being able to eyeball the actual seating depth of the primers in your cases, it is hard to say if they are seated properly or not. You measured them for consistency of depth, but apparently not for actual depth. Can you determine how far below flush they are for comparison purposes?

I got a response from CZ-USA this afternoon. Apparently CZ has had some issues with the FP spring not being strong enough on their 527 rifles. My mistake was "assuming" the problem would be consistent. It's not.

You said you use a hand priming tool - which one? Do you press hard at the end of each priming stroke? I have an RCBS hand priming tool which has worked flawlessly for many years. I press each primer in hard without worrying about depth. The primers are seated quite deep, not just a little below flush. I also use Winchester primers almost exclusively for both handgun and rifle without one single problem.

My hand priming tool came with the LnL kit I bought some time ago. I've used it a lot, and like it. When it comes to priming I tend to be a little cautious. The way I check the seating is sliding a thickness gauge, made from brass shim stock to make sure they're below the surface. I got the depth from an assortment of NIB rounds. With the hand primer tool you can't go far enough to really do any damage, (unless one goes in upside-down). I can sort of "feel" when the primer is in deep enough.

I appreciate all the replies..... Thanks.