The Dedicated .22 Long Rifle AR15


A few weeks ago I talked about the conversion kits for Ar15s. Using the .22LR rimfire round in your AR by swapping out bolts and magazines is thought of as a cheap way to shoot your gun more. Some of them work fine, some great but few give you much accuracy since you are firing the bullet in a barrel with a twist rate that is always going to be much faster than it needs.

Several years ago S&W came out with their answer to this. An AR15 that is a dedicated platform for the 22. The MP22. Duncan already reviewed one and talked about it a few years ago and you can find that on the site already so I will skip all that.

I wanted to compare the accuracy of the MP to the MK261 and the Colt conversion unit. To do this I cheated a little and put a leupold 10x scope on the gun and used Howard’s new piece of kit for shooting off bags. As you can see the MP22 is nearly a dead ringer for a regular AR.

same fire controls and even comes apart the same way

So you can train with it using rimfire without having to use something that feels “off” compared to your AR and without using the iffy conversion kits. So how does it shoot though? Pretty good.

Above are three 10 shot groups at 50 yards. I used federal bulk pack, some Remington bulk crap and some Winchester. It shoots pretty good. This from a bench rest and with 10X of course.

I’m not sold on the idea of using the 22 conversion or AR for training. Yes the gun feels the same with it’s controls but you don’t cope with 556 recoil. or muzzle blast or trajectory or really anything you cope with when firing the 556 or 762 or 300 blk out or whatever it is you like to use. You get some practice with fundamentals but that is really it. The gun doesn’t even weigh as much as a 556 gun. I always found this claim of cheaper training highly dubious. To me, its just a fun plinker or for shooting at birds and chipmunks or something for starting out a kid. But thats just like, my opinion man.

The gun is priced very attractive. That always helps . And it has been ultra reliable. Magazines can be had in different capacities though I can only never find the smaller ones in stock anywhere. It will also accept anything that will mount to a picatinny rail so you can go insane with mounting things to the gun that costs more than the gun if you are so inclined.

In summary, I do think it is a better option than the conversion kit bolts.


  1. Good article. The accuracy kind of surprises me. I have often debated buying a dedicated .22lr AR rifle. However, I have always decided that my Ruger 10/22 was good enough and just bought another AR in 5.56.

  2. I’m leaning towards a dedicated 22LR upper on my 556 lower. Same furniture, trigger, etc, similar weight. Don’t know if I can bring myself to duplicate the 556 optics…


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