I'm running a 9mm CMMG SBR which uses and AR-style bolt.  Started to have ejection problems and I found that the extractor pivot holes are ovalized.  I certainly lube the bolt, but I find now that the recommendation is to lube the pin prior to reinstalling the extractor, easy enough to do after every post-range session cleaning.  Is this failure common when the pin isn't lubed?  I usually use either Slip 2000 or Slip EWL, but I wonder if a relatively light oil has enough staying power to work over 500+ rounds versus using a very light grease.

I use a high temp synthetic grease in mine.

While I don't hav a 9mm I have a 22 dedicated upper from   CMMG that is 15 ish years old and cmmg stands behind their products . Give them a call.

Never saw one on a government rifle. 1st echelon doesn’t even allow the extractor to be removed. The average marine isn’t smart enough to apply oil to the pin anyway.

I’d say it’s a non-issue en masse. Your gun must have just been a defect of some kind like a chattery tool or maybe too-hard a pin? Being a 9mm, I guess the bolt could be soft too and you’d never know.

I’d like to think CMMG will get you taken care of.