Piercing Primers...

[mic2377]

I have been having a problem lately with piercing primers. The last trip to the range, it 2 of around ~65 rounds.

Here is the setup:

18" AR, Nordic barrel w/Wylde chamber, LMT bolt, adjustable gas block

Here is the load info:

PMC brass, trimmed to 1.750

Hornady 75 BTHP

23.5 of Varget

OAL 2.250

CCI-400 primers

I do not think this load is too hot. It shoots great - sub-MOA out of my rifle, and reliability is 100%. The brass seems to look fine, no ejector marks or swipes. The primer is quite flat, however the CCI-400's seem to flatten at WAY below any sort of max load. I suspect that the primers are the problem here, as I read that the CCI-400's are soft/thin and not really intended for such loads.

So, I assume that getting a different primer, IE CCI-450, 41, of Wolf SRM would probably fix my problems, correct? Thanks for your help.

[redial]

The brass seems to look fine, no ejector marks or swipes. The primer is quite flat, however the CCI-400's seem to flatten at WAY below any sort of max load. I suspect that the primers are the problem here, as I read that the CCI-400's are soft/thin and not really intended for such loads.

So, I assume that getting a different primer, IE CCI-450, 41, of Wolf SRM would probably fix my problems, correct? Thanks for your help.

Yup!

If you're shooting an AR, take a close look at the tip of your firing pin. After a few pierced primers, it'll probably have at least a dimple, dead center or has been cut into a sharp point that will make piercing even more common.

Mark

[mic2377]

Got some CCI-450's - working up some loads with them over Christmas. I threw my spare firing pin in and will be running a heavier buffer as I have been noticing a few marks on the rim from the extractor here and there.