Sorry guys, I have been away for a little bit.
I purchased this rifle used and it had been fired.
I deployed without trying it out, and took it out for the first time a couple of weeks ago.
It was a factory Del-Ton rifle and there are no markings on the barrel.
I was using new surplus LC ammunition.
I tried a No-Go gage and it failed to seat riding the bolt forward.
I then let the bolt slam forward and had a hard time getting the gage out.
So something is not right with the chamber.
A No-Go gauge is not suppose to let the bolt close. And, yes, if you slam the bolt closed it is often a bitch to get the gauge out.
Did you try a Go gauge? If that works the chamber should be okay for the caliber you are shooting. But I suspect the many comments about the chamber being screwed up are probably right.
The Butt F**k that sold you the AR should be shot.