New Magazine for M-16/M-4

The GenM3 PMag polymer magazine manufactured by Magpul Industries has been approved for use by the U.S. Air Force and the U.S. Marine Corps.

A bit of small arms news that might have an impact on the Coast Guard in a report from Military Times. 

If I understand correctly, this will be the only replacement magazine used by the Marines, while the Air Force use either this or the Army’s “Enhanced Performance Magazine,” or EPM.

Senators have asked the Army why they have not also approved the polymer magazines.

“The Magpul GenM3 PMag was the only magazine to perform to acceptable levels across all combinations of Marine Corps 5.56mm rifles and ammunition during testing. That magazine has, therefore, been approved for use for both training and combat,” Marine Corps Systems Command told Military Times.

The senators’ letter highlights that the rigorous testing by the Marine Corps of Magpul’s GenM3 PMAG witnessed zero stoppages even among a multitude of ammunition types.

“Additionally, reports state they also reduce damage to the chamber face and feed ramps when using M855A1 ammunition. As our national debt approaches $20 billion, ensuring the longevity of these rifles is important,” the letter reads.

Anyone aware if the Coast Guard has taken a position on these new magazines?

2 thoughts on “New Magazine for M-16/M-4

  1. The Russians have been using plastic magazines for over 40 years.
    It is remarkable that this new magazine will hold ” a multitude of ammunition types.” I’d have to see it load a .50 caliber round to believe it. I am equally skeptical about the “old” magazines damaging the camber face or the feed ramp. One report notes the old and new rounds are identical in length.

    • With the M855A1 ammo, as I’m given to understand anyway, it’s not so much the OAL of the cartridge as it is that the steel penetrator nose is exposed, rather than being under the copper jacket as in the original M855.
      Since the first portion of the feed ramp is part of the aluminum upper receiver, the exposed steel nose has a solid chance of damaging that feed ramp. Or if the round presents too low, the bolt group coming forward can force that exposed steel point right into the rear face of the chamber and cause burrs right at the rear of the chamber, which only makes feeding problems worse.

      As I gather, the older magazines aren’t designed with that little quirk of the newest ammunition in mind, whereas the Army’s “EPM” (which borrows from a couple COTS designs rather heavily, shall we say?) and the PMag GenM3 were designed–or revised, in the case of the Army’s magazines, which are improved aluminum magazines–with M855A1’s characteristics and quirks in mind.
      So it’s not that the magazines per se cause damage, it’s that the new ammunition has characteristics that, when feeding from the older magazines, can (not necessarily “will” but “can”) cause damage to the weapon.

      The further idea with the new magazines (PMag) is not that it takes different calibers/cartridges, but that it can handle all types of 5.56mm ammunition: M855A1, M855, M193, Mk.262 Mod.1, Mk.318, M200 Blank, M196 Tracer, M856 Tracer, et cetera.
      And in a pinch, you could probably load 300 BLK into the thing, as there are persistent Gunternet rumors about some SOF units adopting that cartridge for certain limited roles in the last few years.

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