AR10 failing to unlock from battery

[T-Roy]

Anyone ever had an AR that occasionally won't come out of battery?

My RRA LAR 8 will run fine, sometimes for five rounds, sometimes for 50. But eventually it will lock up, sometimes on a spent casing, something if you drop the bolt after removing an empty mag. I've replaced the firing pin thinking it was possibly bent and locking the bolt, not allowing it to rotate and unlock. Well that didn't work, had the same issue today.

I'm sitting here tearing it apart and the firing pin retainer is bent. I'm thinking the retainer could be rotating some as the action cycles and at some point the low side catches on the firing pin and locks the bolt.

Thoughts? Anyone had a similar issue? Regardless I'm going to replace it.

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[BigMike]

Nothing obvious burred on the chamber or lock Iocking lugs?

 

[T-Roy]

Nothing obvious burred on the chamber or lock Iocking lugs?

Nope. And last night when I managed to get the bcg out without mortaring the piss out of it (what I've been doing) the bolt wouldn't move its full range in the carrier out of the gun, so the problem is theoretically in the bcg. As soon as i pulled the retainer it would move freely again.

Gas rings look good, not a bunch of carbon on the bolt. I really think the retainer is the issue. But I've never heard of a bent retainer taking an AR out of action before.

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[BigMike]

If the retainer is walking out of the bolt carrier, the inside of the upper will be scored up where it's hitting. You can roll the firing pin on a flat surface to see its it's bent.

 

[CTS Tactical]

The only time I have seen been firing pin retainer is from over pressure loads. Are these factory or hand loads?

 

[T-Roy]

The only time I have seen been firing pin retainer is from over pressure loads. Are these factory or hand loads?

I've only put factory ammo through it. Mostly 147 gr ball. But I bought it used so who knows. It's been wn ongoing issue since I bought it, so I think i bought a problem.

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[jeep78]

Do you have a known good BCG you can try to see if your original is bad?

 

[CTS Tactical]

I've only put factory ammo through it. Mostly 147 gr ball. But I bought it used so who knows. It's been wn ongoing issue since I bought it, so I think i bought a problem.

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It would make sense to me if a box or two of hotter loads got mixed in to a larger lot. It would explain the fact that it is a very intermittent problem. I think I would pick up a few boxes of off the shelf ammo and see if the rifle fires and cycles all of it without a problem. Might help to isolate the problem.

 

[T-Roy]

Do you have a known good BCG you can try to see if your original is bad?

No, only ar10 i own

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[mcdougmd]

Call RRA and talk to customer service.