As long as the magazine is catching in place and locking properly... The magazine feed lips are not allowing the left side round to sit high enough to feed. Try to bend the rear lip (the one holding the round down) up just a very little bit at a time until it feeds. Take care not to go too far as this will cause double feeds. You may also need to alter the front lip, but only if the nose of the round is catching the feed ramp at the rear of the barrel on it's way out.