Twice now I've fired one magazine of South African .308 through my Springfield M1A with two failures to extract per mag. The first two times I had to get a cleaning rod put down the barrel and whack the casing out (with '79 ammo from a gun shop), the second set were easily extracted after letting the bolt fly home manually and pulling on the charging handle (this is with '81 headstamped stuff from AIM).

Does this sound like an extractor-related problem or an ammo-related problem?

Sounds like the chamber or the bolt is dirty, I have never had any problems with the South African .308 ammo

I shot SA ammo this weekend through (2) different M1As without any issues.

Does your M1A have a USGI bolt or SA Inc. bolt?  

Try a new USGI extractor.  It's an inexpensive part to see if it will resolve your extraction problems.

To me it sounds more like what dpmmm said.  What model is your M1A?  It's possible if you have a loaded or NM that the chamber is a hair to tight for that brass.  I don't know.  Does that sound correct  to ya'll?

Are you sure it's not short stroking and pushing the empty back into the chamber?  That will cause the type of jam you are talking about as well.

Whoops, sorry for the delay. I kinda forgot I posted this.

I don't think it's a dirty chamber issue, since the gun works 100% with Australian ammo.

The bolt is Springfield, non-GI.

It is just the standard model, with USGI chrome-lined barrel from 1962.

May I ask what "short stroking" is? Whenever the jam occurs, the casing stays in the chamber, while the bolt goes back far enough to strip off the next round, and that next round always gets stuck smashing into the jammed case.

Also, the finish on the extractor just looks a little "different" than the bolt/other SA parts, so I'm tentatively thinking it might be USGI (I hope it isn't, since just getting a new extractor would be an easy fix).

Thanks.