Just got a B14R this week and mounted it in a KGR Bravo. It's working well except for the magazine, it's not all the way up. It will feed the first 3 to 5 rounds just fine and then I must push on the bottom of the mag to get it to feed those last few. It moves up just a tiny bit when I push on the mag. The KRG manual says you can adjust that but it doesn't say how!