M&P 15-22 Magazine Adapter

Last Sunday, I shot a pin and plate match at a local range. One of the shooters had a .22LR AR SBR. His SBR uses M&P 15-22 magazines. I asked him how this was possible and he showed me the magazine adapter called “Better Mag”. It is made by Redimag and allows for the use of S&W M&P 15-22 magazines in almost any AR-15 magwell. The adapter will even hold the bolt open on the last round.

Here is a video that details the installation.


The Bettermag retails for $39.95 and can be purchased on Redimag’s website.

Nicholas C

Co-Founder of KRISSTALK forums, an owner’s support group and all things KRISS Vector related. Nick found his passion through competitive shooting while living in NY. He participates in USPSA and 3Gun. He loves all things that shoots and flashlights. Really really bright flashlights.

Any questions please email him at nicholas.c@staff.thefirearmblog.com


  • Reef Blastbody

    Are S&W M&P22 magazines significantly cheaper/better than comparable .22LR AR pattern magazines, like Black Dog to drive market demand for a product like this?

    • Sam Schifo

      Prices for 25 rounders on Brownells; 15-22 mags are $20, Black Dog mags with steel feedlips are $24, and Black Dog mags with plastic feed lips are $16.

  • Paul Dawson

    As far as quality goes the Black Dog magazines seem to be much more study than the M&P15-22 magazines. Some of the newest Black Dog magazines even have a metal feed lip, although I’ve never had any issues with the polymer feed lip magazines. I guess it depends on the upper receiver you want to use use, but it would have to be one heck of an upper to make me want to use M&P15-22 magazines. The Tactical Solutions & Spikes Tactical receivers, among others work with the Black Dog and are of excellent quality. The SIG 522 even ships with Black Dog manufactured magazines.

    • The build quality may be better on the BDM magazines, but I found that M&P 15-22 just feeds so much better, and most people think it is due to the magazines.

      • Paul Dawson

        That could be partly due to the gun the magazine is mated with. On my 522 I rarely clean it (as in maybe ever 1500 rounds) and I’ve never had a single FTE or FTF using cheap bulk ammo and the original polymer feed lip BlackDog magazines (I have 4 of them). My experience with the newer metal feed lip magazine is much more limited. I haven’t put that many rounds through the magazine, but still the same results are the same as the old version. The 50-round drum I have no experience with.

        From what I’ve seen with my own use any FTF or FTE issues using the BlackDog magazines, running different versions made over different periods of time, would likely be more gun induced than magazine induced. My brother has a drop-in .22lr conversion on his M&P15 5.56mm and reliability with that is questionable which I fully attribute to the conversion. He also has a 522 and it runs well dirty just as mine does. I’m planning on picking up one of the Tactical Solutions uppers this summer. Although I know it will be better than the drop-in conversion I won’t hold my breathe on it being as reliable as the SIG522.

        That said, the M&P15-22 magazines may run very well. I have no personal experience with them to base any opinion on beyond comparing them side by side to the BlackDog. Construction/build quality-wise I would have to give that to the BlackDog – the body is much more sturdy and doesn’t feel cheap in the hand. Certain uppers may very well run better on the M&P magazines – I would love to compare the two and see the results on both the drop-in conversion kit and a high quality dedicated upper receiver.

  • Duder

    I have the Ciener conversion and use it all the time on my various length AR uppers with Black Dog Machine mags and have never had an issue. It also has the last round bolt hold open.

  • Cymond

    Also look at Catch22, a company that makes stickers and a specialized bolt catch for the M&P magazines. Of course, installing the bolt catch means dedicating the lower rimfire almost permanently. However, they also sell stickers that attach along the spine of the M&P magazines which allow them to work in an unmodified mag well.