I bought new upper and lower .300 blk receivers and put them together, as a pistol. I never attached a brace to the pistol. I tried shooting it at the range for the first time and it wouldn't reliably cycle supersonic or subsonic rounds. I was using an attached Surefire Socom .300 blk suppressor when attempting to shoot the subsonic rounds. What was happening was the fresh rounds would get jammed between the magazine and the chamber as the weapon cycled. I would manually load a round into the chamber and then it would jam again right after I fired it. I tried cycling it using the charging handle and the rounds would occasionally jam as well. I never limp wrist when I shoot and I've never had this problem with any other AR pistol, including my other PSA .300 blk pistol. Has anybody else had this problem?
David