So I bought a S12 about 4 months ago, and when it arrived, I took it out of the box, looked it over, but not in any great detail, and took it out and ran a box of 2 3/4 shells though it, and put it back in the box where is sat untouched for 4 months until today. I was going to start a conversion on it so I started to field strip it and I notice these little cracks in the end of the bolt carrier where the gas piston screws into the carrier. Now I have built a lot of AKs and have seen new and well used carriers and have never seen cracks like these before. Had anyone else noticed cracks like