Not a direct help, since I have no experience with aftermarket mags, but if you can't get that integral 20 rounder to work well consistently, then I'd suggest putting the stock 10 round magazine back on and buying some surplus Yugoslavian M67 (in the 40 round boxes) to get the quality stripper clips for rapid reloads. It's currently available at SGAmmo or Sportsman's Guide. In my experience the NC Star strippers are junk. I can tweak some of them and get them to work but none of them work as well as the Yugoslavian strippers.