One Way The CMMG Mutant Is Different

    Partially as a result of the AK’s success, non-Kalashnikov designs utilizing the magazine of the 7.62x39mm Avtomat were few and far between until very recently. Due in part to civilian demand, in part the needs of special forces, and in part to countries armed with aging 7.62mm AK rifles looking to replace them – but not their magazines and ammunition, which are often still in production – there has been something of a resurgence of designs based around the venerable 7.62x39mm cartridge and the tough-but-heavy AK-pattern magazine.
    At the 2015 SHOT Show, as Troubleshooter Berlin and I were wandering the floor, he mentioned that the magazine wells of some modern designs provided insufficient or improper support to the magazines. Naturally, we decided then to seek out as many of these rifles in the show as possible and compare them. While we were able to take a look at all the ones we could remember, in a few cases I did not have the presence of mind to take photographs, so this article will be supplemented with photos taken from the Internet. First, and most important is the AK rifle itself. This firearm supports its magazines in six areas: Front, rear top, rear bottom, each side, and the front top, indicated below:


    Picture showing the support areas of the AK magazine. The part that most concerns us is indicated by the red lines. Image source: Troubleshooter Berlin.

    The front and rear supports are most obvious to a designer of a new firearm using these magazines; also evident is that the front sides of the magazine where it is reduced in diameter also need support (not indicated in the above picture). What’s often neglected, we found, was supporting the top of the magazine, indicated in red in the above image. How does the AK magazine support this area? A view up through the magazine well will show us:

    Highlighted in red, the two wings that support the AK magazine against tension and over-insertion. These are critical areas for proper functioning. Image source:, modified by author.

    Next on our list is the SIG 556R, one of the rifles of which I did not manage to take any pictures:

    2015-02-09 22_38_19-D6OmZAC.jpeg (1983×2644)

    SIG did not have any AK magazines at its booth, so I was unable to see how the raceways shown here interacted with the magazine. However, it’s evident that they don’t reach in as far as the “wings” on the AK’s trunnion, and further, as they are straight and extend all the way to the rear of the magazine well, they cannot support the top front of the AK magazine, which is stepped down. Image source:

    The Rock River LAR-47 is a similar rifle to the CMMG MK 47 that was announced three years ago:
    2015-02-09 22_13_38-SHOT Show 2012_ Rock River Arms LAR-47 Rifle - YouTube

    This somewhat dark image – a still taken from a video – shows the inside of the magazine well. No support is apparent, but a different angle may be called for. Image source: Guns & Ammo’s Youtube channel.

    2015-02-09 22_10_07-Rock River LAR47 7.62x39 Rifle Shot Show Review - YouTube

    Another screencap – blurrier, but the lighting is better. The lack of support is evident in this shot. Image source: modernpawn’s YouTube channel.

    Another AR-15 offering that supports the use of AK magazines, the MGI Hydra multicaliber rifle:


    The MGI Hydra uses a modified pattern of AR-15 upper receiver when using the AK magazine well. As a result, it does not provide the correct support for the top of the magazine.


    The extra relief needed for AK magazines to fit is evident in this photo.

    Finally, the CMMG MK 47 Mutant:


    Two “wings” in the upper receiver protrude, showing the support given to the top of the magazine by the MK 47’s upper receiver. Further, wear is evident on the PMag-AK’s top front surface, giving proof that the MK 47 is supporting the magazine as it should.


    The MK 47 properly supporting the magazine in its receiver.

    These pictures make one thing clear: Among the non-AK designs utilizing this pattern of magazine shown here, the MK 47 is the most well-designed with respect to magazine support. Is the demand for this sort of rifle great enough that CMMG’s attention to detail will win out over its competitors? It’s difficult to know, but I’m sure owners of the MK 47 will appreciate it, anyway. EDIT: I emailed Brandon Novotny of CMMG about this, and he had this to say:
    “The “wings” are most definitely magazine supports. They keep the front of the magazine from pivoting upwards during firing and have nothing to do with guiding the rounds into the chamber. The radii cut from them was necessary in the machining of the feed ramps into the upper.One thing to note that not many people notice is the benefit of the LR308 barrel extension. It has wider feed ramps in it compared to an AR15 which allows the round to more easily feed into the chamber. I’ve seen some AR15s have issues with the M4 feed ramps being too narrow for the larger case of a 7.62x39mm.”
    Nathaniel F

    Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. He can be reached via email at [email protected]