My new build had the same issue. Case stuck in chamber, extractor tore off part of the case rim.
How well did you clean your barrel/chamber? Get a AR chamber brush and give it a good scrubbing. Didn't need anything rough,I just used g96 3 in 1.
And that was on a $300 faxon barrel. But there was something in the chamber causing friction and jamming up cases. Wasn't visible to the eye.
I keep my guns very clean, I clean my guns after each trip to the range. I scrub the hell out of the chamber with chamber brush too.
In your case, was it the built up carbon in the chamber? or something made its way to the chamber