Project Report: Shortening M&P 15-22 Mags (For Appleseed)

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  • techres

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    Project Report: Shortening M&P 15-22 Mags (For Appleseed)

    The M&P 15-22 makes a great AR training tool and I am loving mine. The only downside that I have with the rifle is with the lack of magazine options that are currently available. Right now there are 26 round mags (red followers) and 10 round mags (blue followers). This makes sense except the 10 round mags are the same length as the 26 rounders and despite early talk of a new set of magazines, none have been seen in the real world to my knowledge.

    Why short mags? Well, a shorter mag gives a distinct advantage in getting low to the ground for the type of prone shooting we do at Appleseed. The short mag both allows the shooter to get lower but also is easier on magazine changes in the same position.

    So the only option is to adapt, and by that I mean the magazine. Following what others had mentioned trying, I ordered 3 mags from a dealer in TN and had them in less that 48 hours (nice guy!). The rifle only came with one mag and I wanted 2 full capacity and 2 lower capacity (8-10 rounds).

    This is what I got in the mail:

    4488143000_ee1752a574_b.jpg



    I began by scoring the spot where I wanted to do the first cut:

    4487501563_a0ec542052_b.jpg



    The I pinned down the follower and spring:

    4488171370_2dda329d73_b.jpg



    Then came the cutting which I did with a small saw:

    4487503913_4a98aa2630_b.jpg


    After getting the magazine into two pieces, the spring, follower, magazine horizontal bar, and "floor retainer piece" all came out easily. BTW, the plastic is thick and makes a powdery mess when cutting. I got to use the vacuum a lot.

    4488155342_677ef41abf_b.jpg


    4488140770_d672d46f49_b.jpg


    4487526295_99913aa724_b.jpg



    Now I scored and cut the bottom piece that would become the "bottom plate":

    4488163592_de31f69d07_b.jpg



    The cuts were not perfectly level so a file was used to level the pieces that were to be matched:

    4488173296_6f3cd11212_b.jpg


    This took a long time and was followed by a knife to clean up the edges:

    4488145258_3ae0edac8f_b.jpg



    Finally I clipped off 1/3 of the spring, epoxied the bottom back on as best I could and secured it together to dry. Here is the final product:

    4488168680_73557d3e6b_b.jpg


    4488148408_41264ba491_b.jpg



    She looks good unloaded, but I needed to do a quick check of an 8 round mag. The rounds loaded easily and felt like I could get in 10 pretty easily. This is 8:

    4488161514_6a5cf637c9_b.jpg



    All in all, it was a very easy mod and was done on the couch while working on other things and watching a red dwarf episode with the kids. Now that I have one down, I am going to do a second and try to make this one look nicer.

    Tomorrow I will take them to the range to be sure of their function, but I am pretty sure that they will be just fine.

    For anyone with an M&P 15-22 and a need for a shorter mag, just do it. It is really quite easy!

    Techres
     

    pudly

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    Looks very good. :yesway: My concern would be with the full-sized spring in a shortened mag. Please report back after some field tests on how reliable it is.
     

    techres

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    Looks very good. :yesway: My concern would be with the full-sized spring in a shortened mag. Please report back after some field tests on how reliable it is.

    I clipped the spring, taking off about 1/3'rd of it. The 'feel' is about right. We will see!
     

    mettle

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    Nov 15, 2008
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    Why? I know Appleseed is all about the 3 positions for highpower shooting (which is irrelevant in reality but relevant for position shooting skills); but, why are you cutting up the mag? A typical AR mag can be implemented (30 rounder) in prone....? Or, are you just trying to limit capacity for the prone AQT portions?
     

    techres

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    Why? I know Appleseed is all about the 3 positions for highpower shooting (which is irrelevant in reality but relevant for position shooting skills); but, why are you cutting up the mag? A typical AR mag can be implemented (30 rounder) in prone....? Or, are you just trying to limit capacity for the prone AQT portions?

    A 30 round mag can impede getting the left elbow under the rifle as far as possible as well as monopod on people with shorter arms. Additionally, the mag change in prone is faster and requires less movement with a shorter magazine as you do not have to rotate/cant the rifle to clear the mag out of the magwell.

    Many clear the course of fire just fine with a 30 round AR mag. But many shooters also find a Colt 20 round mag a huge blessing and a whole different shooting experience.

    These cut mags attempt to mimic the Colt 20 round mag experience.
     

    unforgiven1203

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    I've never had any problem with the .223 30 rounders (except with 4 inches of snow bunching up under my mat), but I've noticed that thinner people are more likely to have this problem.
    techres shoulda been a gunsmith or at least a gunwriter!
     

    techres

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    I went to the range this morning and tested the mags. They worked as well as the originals. Here is a video comparing the two in prone (2x 5 rounds from 26 round mags and then 2x 5 rounds from 10 round mags). You can see how the larger mags require more positional changes to get through the insertions and ejections of the mags:

    [ame=http://www.youtube.com/watch?v=_LZM7w77cMk]YouTube - Comparing M&P 15-22 Magazines in Prone: 25 Round Originals vs. 10 Round Short Creations[/ame]
     

    indyjoe

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    Have there been any shorter mags released yet for this rifle?

    I haven't gotten one of these yet, to play with the mag, but it looks like you lost the disassembly capability of sliding the black pin out though the opening on the bottom. Drilling a hole there before epoxying on the bottom should fix that.
     

    techres

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    Yeah, they saw the need and made the mags. I will be ordering a pair for myself. These work well as 5-7 rounders but get flakey at 10 if you are trying to do an entire 400 round appleseed weekend.
     

    hotfarmboy1

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    I just now saw this. I will be buying an M&P15-22 here soon. And I will either do this or order a couple from the S&W website. Very nice writeup and vid, I tried to rep you but I'm out for now.
     
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