When I was in the Marine Corps, I remember signing for and being issued 6 of the standard metal magazines for my rifle out of my unit armory. Some of these magazines were older than myself and others who were in at the time, and they showed it. They were covered in dents, dings, scratches, etc. These magazines were extremely problematic and made it to where it was considered normal for you to have to slam the magazines into your rifle in order to get it to seat properly. In many cases, if you damaged your magazines, you were expected to buy new ones out of your own pocket. Now Magpul PMAG Gen3 magazines are approved by the Marine Corps to be purchased by individual units for their Marines, if they so choose.
This decision hit me as being one of the best decisions the Marine Corps has made, among many others, in their attempt to remain at the cutting edge with their warfighting capabilities. How does this make them cutting edge though? Let us consider the fact that our rifles are lightweight, magazine-fed, gas-operated, air-cooled, shoulder-fired weapons. The one part of the rifle that is foreign, the magazine, is the single thing that will determine whether the rest of the weapon works properly. If you can not get your ammo to reliably feed in your rifle, you no longer have an effective means by which to fight with that rifle. Currently, polymers have proven to have superior durability and longevity over metal in many firearms.
Polymer magazines like the PMAG have a couple of advantages over the standard metal bodied magazine, which end up making them better suited for long term abuse in the military, especially the Marine Corps. Polymer as a whole does not permanently deform like metal, and typically have better overall strength in comparison. Landing on magazines and stepping on them while at the range can cause permanent damage to metal STANAG magazines, while polymer mags take it in stride as if it is nothing. Polymer magazines are also not very sensitive to temperature changes, which can cause metals to become brittle in some cases where they are constantly seeing transitions from severe heat to extreme cold. And lastly, disassembling polymer magazines are much easier in general, which makes it easier to clean and maintain them as a whole. These little things can and have made a big difference in magazine performance.
The Marine Corps has only approved the magazines for units to buy with their individual funding that they get, but I am hoping to see a military contract go to Magpul in the future for these magazines. I remember some of my guys were using PMAG magazines when I was deployed. We weren’t restricted to using issued gear in my unit, but I know that some units do restrict the use of certain pieces of gear, which is unfortunate. Perhaps we will see the Marine Corps get a contract with them in the future if testing proves the mags to be worth the investment. I know that the Australian military is currently working with Magpul to provide them with their new AUG magazines, which is a pretty cool deal. Time will tell.