I had the extreme good fortune to receive the magazines in for review. I have had extremely disappointing experiences with complete polymer magazines before, and was extremely skeptical of their ability to take a beating and keep functioning. Much to my surprise, they took the worst I could throw at them and kept on working. Add to that some unique and pleasant design features and you have some magazines that are ready to rock out of the box. Though there were some minor fit issues, that could be attributed to the dimensions of my lower receiver, but aside from that, these work great.