Some Arfcommers have reported compatibility issues with the new Magpul PMAG Gen M3 magazine. The over travel stop on the M3 can prevent it being inserted into some AR-15 lowers with oversized trigger guards. POF, Noveske and Spike Tactical billet lowers have been identified as having this problem.

I asked Magpul’s Drake Clark about this issue. He made this statement …

The M3 design was based off years of feedback from endusers. We knew going into the design phase that there are some lowers that are not going to work with the M3 as the magwell spec they are built to is different from the original Colt design, specifically in the area where the over travel stop interfaces with the area just forward of the trigger guard. These lowers represent less than 1% of the total lowers in the marketplace. We already had direct communication with a few manufactures who build lowers with conflicting interfaces, including POF. Changes will be made to their design to allow comparability. When these changes will be introduced into full production I am not sure. I can say some that have recognized this issue have already been addressed it, such as Noveske.

And for those that have older design lowers that are not comparable with the M3, they have two choices. Use the MOE PMAG or modify the M3 by removing the over travel stop to allow for proper interface.

In all fairness to Magpul, the M3 is compatible with more firearms than any of their previous PMAGs. For >99% of users this will not be a problem. I expect the few manufacturers who are producing incompatible designs will soon change them, it being an easy issue to address.

[ Many thanks to jdun1911 for the tip. ]