I know there was a thread on this subject a couple years ago, and it seems a lot of shooters had no problem with Thermold. I bought two 20 round and two 10 round mags, but I'm having problem with them in my DPMS Prairie Panther. The rounds don't feed consistently, and I often end up with an empty chamber. I also noticed that when the bullets are seated, in comparison to a metal clip, the thickness of the feed lips on the plastic mags, keep the cartridge lower in the magazine. (See the attached picture.) I bought my AR for hunting, and plinking, so not big deal, but for self defense, this would not be acceptable. Does anyone want to swap or buy these? PM me.