I don't think an ejector spring would be the problem,but brass scrapings from hot loads can wedge up the ejector.That can prevent the case from seating into the bolt face,and therefore it is not centered up .I just see that watching cartoons in my head of the gun running.I may be wrong.
Taking a bbl extension off is ill advised.My understanding is they are torqued to 150 ft lbs and loctited.Re-assembly is not about torque,the bbl extension must be indexed to the gas port.
The case dia at the head is 376,so the chamber might be a couple thousandths bigger.Maybe if you got some fine 1/2 in dia mounted grinding stones with1/8 in shanks,maybe a round one,like a cherry,and a cone one like a pine tree,then you might have to dress one with a piece of carborundum to be about 120 deg,like a drill point.Get a tool called a pin chuck or pin vise.General makes a cheap set.No motors,no electricity.Using just your fingers and light pressure,what you will do is a bit like cutting a 3 angle valve job seat.Ink it with magic Marker to see progress.Start with the cherry.Spin it till to get maybe a ten thouandths corner break.Then ink it again,and just get maybe a 5 thousandths break with the other two stones.
Do not touch the chamber walls,work only on the edge.!/2 in tools should not enter.I would not consider a Dremel or drill.
Then you might sharpen a 1/2 in hardwood dowel to a90 degree include point,and put some 600 or 900 grit lapping compound on it,and spin that between your fingers a bit for a little polish.
Now,realize,I have not done this to an AR.I made the whole thing up.But it is what I might try.Then,of course,do a serious immaculate job of flushing,blowing all trace of grit out,then put a rust preventive in the chamber,bore area.I have seen barrel steel rust in minutes after a degrease with solvents.
Certainly,check out other options first,and get a second opinion from a gunsmith or someone AR knowledgable.This is not the first thing I would do.It bothers me the gouge is so far forward.Looks more like the rear end of the round is not coming up
Last edited by HiBC; April 4, 2010 at 02:47 AM.