I had a similar problem on my mke. Try putting the mag follower and spring from a pof mag in an hk body. If it still doesn't work you probably need to open up the feed lips a little more so rounds come out of the magazine easier. I used 2 vice grips to do this to all of my hk mags. It doesn't take much at all so don't over do it. Next time you hit the range just bring some pliers or vice grips to play with the feed lips. Good luck!