I know I need to post the Question over on the AR15 website but since I was here thought I would ask.

My buddy and I have RRA AR15s they they have tight chambers. He said this morning he was seeing a slight dimble on any and all rounds that are chambered then ejected without firing. He asked me is this was normal. I had never noticed but told him I would check next time I had it out.

Is this normal for the AR15? I know that they do make harder primers for slam fire issues.

That is normal. The AR15 firing pin is not held in place by a spring so it moves around freely. When the bolt goes into battery the firing pin moves forward a little and causes that dimple.

Forrest

it is normal. if you want to spend a whole lot of money you can buy a titanium firing pin and it will be less noticeable.

The floating firing pin causes that for the exact reasons listed above. This phenomena is not uncommon in military rifles and even the venerable M-1 does it.

CCI #41 mil-spec primers are helpful if you're concerned.

quote:

CCI #41 mil-spec primers are helpful if you're concerned.

And they can be a component of some rather accurate loads too.

Thanks guys. I thought that might be the case. I had just never noticed it. Guess I don't eject many unfired rounds.

They are the RRA Varmint A4 so the chambers are tight on reloads even with a small base die. So you need to allow the bolt to slam home to insure chambering.

He said the dimple just shows and we have NEVER had a slam fire. Next time I buy small rifle primers I might try the CCI. Can't be too safe.

Worst problem with these rifles is finding a load that doesn't group sub MOA. Even the surplus will group sub MOA. Plus every load we have tried for 40gr up through 80. Heck of a problem to have.

Regarding primers, the CCI, Federal 205/M, Remington 7 1/2, and Wolf SRM/223 are all considered suitable for the AR15. Don't use Winchesters as they are prone to pierce even with reasonable loads. When they pierce, the firing pins gets eroded and you have to replace it.

The funny thing about this is how many people in the Army do not realize this is normal and freak out when they first see it.