I recently bought a Shield .45. I have somewhat the same problem. I've only used the 7 rounder, but it won't chamber a round with 7 in the mag. So I load 6, chamber one, then pull out the mag and then it will take the 7 rounds in the mag. I had one actual FTF, but I think that might have been me limp wristing??, but pulling the slide back to chamber a round, I'm having some issues. Slide feels quite gritty when racking also.