UPDATE: Drake from Magpul emailed me to say this was an issue with just one batch and it has been resolved.

This was a very small batch of PMAG’s that had this issue. We addressed the issues internally and solved the problem. We also followed up with all of our customers that we thought may have received these issue mags. Problem solved.

There is a discussion at the M4Carbine.net forum about Magpul polymer PMAGs cracking. Steve from Triad Tactical was running a training program and noticed a bunch of the PMAGs cracking in the same spot.

By the end of the first class, 50% of the pmags were broken. All of them had split where the feed lips meet to form a V on the spine. I called Magpul and they over nighted me 50 new pmags and a prepaid return label for all 50 of the ones I had, broken or not. They asked me a bunch of questions about the who, what, when, where and how the mags had been used. This was very cool and I was pleased with the way it was handled. I was back on track and had one course of 26 in the books, 25 to go.

More here.

The moral of the story is that diversity is the key. Don’t rely on one brand of magazine, especially if you are buying a whole lot at once. If a batch is faulty, regardless of wether it is metal or polymer, and you bought a whole lot you are screwed.

Many thank to Jay for the link.