I shot about 1/2 case of SP barnaul 5.45 x 39 on sat. and I also noticed that I would get some interesting jams about every 150 shots. I would look into the gun and those shorter SP rounds I guess may bounce of the feedramp and then they stand straight up in the magazine as the bolt closes 1/2 way on the case.
However, I shot side by side with open sights at 200 meters with a flat top ARand was able to his a standard IPSC target about 1/2 the time... The AR flat top guy next to me was a little upset that my rig did so well. He was drilling it 100% of the time though. So i didnt see any accuracy issues, I will have to try the FMJs later at the same range and see if I hit it easier.
I have a sweet video of me shooting my krink that day:
Big fire balls
Empty a 30 round mag in 4.5 seconds..
I am getting the SBR papers in on monday and hope it goes quickly.
Anthony