AR weird problem - sheared extractor pin

[bjmac]

I apologize. I'm overly cautious of off posts online. Replace it and keep an eye on your spent brass for a while. Or be proactive and inspect and/or replace wear parts... not that an extractor retaining pin is a wear part.

[Bang]

Did some searching on AR forum and generally searched for broken extractor retaining pin and did not find anything indicating that it is anything other than, as already characterized....weird. I would say though that since it sheared at two places where shear can occur, the pin could not be made of a material meant for the job. I think a replacement pin will not break (shear). Interesting that steel ammo was being used at the time, but I don't think steel should have caused it if the extractor is configured correctly.

[Emptymag]

[staylo]

[danhr]

post picture of the extractor and spent casings.

preferably also of the bolt, chamber, and cam pin

Usually stuff breaks for a reason. It's really easy to chalk it up to a bad pin. But if something else caused it, it going to shear another pin. You might not be as lucky next time, and you could potentially hurt yourself.

[dkf]

Better post a dirty pic of your wife and your set of fingerprints too just to be sure...

[bjmac]

post picture of the extractor and spent casings.

preferably also of the bolt, chamber, and cam pin

Usually stuff breaks for a reason. It's really easy to chalk it up to a bad pin. But if something else caused it, it going to shear another pin. You might not be as lucky next time, and you could potentially hurt yourself.

I agree.
It's easy to chalk things up to "eh bad part" but these parts are mass produced... meaning many thousands would be having the same issue.
Why the extractor pin sheared without extractor breakage baffles me.

[Bang]

If the pin had not sheared, the extractor might have been damaged. In this case, the pin sheared and saved the extractor, just like shear bolts on a snow thrower prevents damage to the power train. It would have been great to save the exact steel case the pin broke on and look for damage to the case.

A question. Which would apply the most shear pressure to the pin....the slamming home of the bolt, with the bolt trying to climb up and over the case rim but momentarily unable for some out-of-spec reason; or, the gasses acting upon the bolt carrier while a momentarily stuck case is eventually pulled free. I think the gas-activated extraction phase is the more violent and has more energy than a BCG driven home by spring pressure.

If I am correct, I think the answer may lie in inconsistent loads produced by Ivan, Vladimir and Company.

[KCJones]

post picture of the extractor and spent casings.

preferably also of the bolt, chamber, and cam pin

Usually stuff breaks for a reason. It's really easy to chalk it up to a bad pin. But if something else caused it, it going to shear another pin. You might not be as lucky next time, and you could potentially hurt yourself.

I didn't think to save the casings... Mostly too busy being pissed off and cursing at the jams.

She's all reassembled with new pin at the moment, and honestly just don't feel like going and taking it down again to photo the extractor. Going out for first shooting tomorrow and will clean and inspect afterward. Will post photos then...

I did look everything over carefully and all seems well, nothing damaged or funky.

[KCJones]

If the pin had not sheared, the extractor might have been damaged. In this case, the pin sheared and saved the extractor, just like shear bolts on a snow thrower prevents damage to the power train. It would have been great to save the exact steel case the pin broke on and look for damage to the case.

A question. Which would apply the most shear pressure to the pin....the slamming home of the bolt, with the bolt trying to climb up and over the case rim but momentarily unable for some out-of-spec reason; or, the gasses acting upon the bolt carrier while a momentarily stuck case is eventually pulled free. I think the gas-activated extraction phase is the more violent and has more energy than a BCG driven home by spring pressure.

If I am correct, I think the answer may lie in inconsistent loads produced by Ivan, Vladimir and Company.

Could well be. The only 'variable' different than usual here was that ammo. I also tend to agree that the gas-powered extraction phase likely places more force than a spring.

That makes me think I should pay some attention next time for signs of over-gas: to where the shells are flying out, failure to lock-back on empty mags, etc. Might be slightly-overgassed, but doesn't "present" with brass, but steel put it over the top. If seeing indications, might be worth trying a heavier damper.