The Ultimate Firearms Magazine for the Gun Lifestyle

MAGPUL – Why 40 rounds?

As you’re no doubt already aware, MAGPUL is shipping a 40 round capacity PMAG. Thus far it has met with widespread approval and successful testing (that I am aware of) but I wondered since the news broke, why 40 rounds? What was the reasoning? Why not 35, or 50? Was this some sort of (righteous) marketing protest enacted in response to the shameful actions of CO State Rep. Rhonda Fields, Sen. Evie Hudak’s and their sad, ill-informed and willfully obtuse cronies in that state’s Congress? I was genuinely curious.

So I asked MAGPUL’s Duane Liptak, Director of Product Management and Marketing. (Note: though that sounds like an office billet, Mr. Liptak is a former shooter and instructor with extensive experience.)

“…40 rounds is a number was the number we arrived at for a few reasons,” Liptak responded. “Any longer and a double-stack mag gets unwieldy. It also becomes very difficult to make a conventional magazine carrying more weight than 40 rounds…that will be a truly durable and reliable feeding device.  So for form factor, usability, and reliability, 40 rounds is a nice package…The PMAG 40 has run through endurance tests of 8000 rounds per magazine, as well as our normal battery of drops, dust, compatibility, and abuse, so it’s not a novelty item.”

MAGPUL   Why 40 rounds?  photo

As for timing, it appears to have been largely, if not entirely, coincidental. There was talk of 40-round magazine long before the latest anti-Second Amendment madness started.

“I’m not saying we’ll stop there,” Liptak continues, “but in order for more than 40 rounds of capacity to work as well as we require, it would look and work a little different from the rest of our magazine line. As for timing, as you probably know, we initially announced the 40 several years back, but we couldn’t make it as reliable  or as durable as we wanted to in order to meet our standards until the Gen M3 technology made it possible. So, largely, the timing of the 40 was based on the timeline of Gen M3 development. There is a certain poetic element to the release timeline given recent political events, but the timing just worked out that way.  Well…for the most part….”

MAGPUL   Why 40 rounds?  photo

If you’re unfamiliar with the mechanics of the new magazine, it adds 10 rounds to the ‘standard capacity’ GEN 3 PMAG, increasing overall length by just over two inches (2 1/8″). It maintains the platform compatability as the AR/M4 Gen3 and will, according to MAGPUL, feed reliably at high cyclic rates of fire (an assertion which initial tests, including Iain’s look in Arizona, consistently confirm).  The 40 round PMAG will feed the HK416/IAR/M27, theM249, the MK18 and virtually any conceivable AR15/M4 variant. In the official MAPGUL video they are using M193 5.56mm NATO ammunition and a quick check through various reviews and YouTube videos available make it pretty clear the 40-rounder will reliably allow digestion of most other breeds of that caliber (as well as .223).  One thing I haven’t seen anywhere is how it treats various grain Hornady TAP ammunition – once I get my hands on a 40-rounder I will advise.

Below are the compatibility demonstration video from MAGPUL and the earlier video from RECOIL Editor Iain Harrison.