American Tactical Unveils MP40 Collapsible Stock and 9mm AR-15 Adapter

If you have an MP40, American Tactical’s new stock will make it even more fun to shoot.

Earlier this year we reviewed the German Sport Gun MP40 imported by American Tactical (ATI). It’s fun to shoot and a great tribute to WWII, but, as we said in the review, it would be really fun with an authentic-looking collapsible stock.

American Tactical stepped up to the plate, and we got a chance to check out their new product at this year’s NRA Annual Meetings & Exhibits.

The MP40 collapsible stock is constructed from 6061-T6 aluminum right here in the USA. The entire stock, including the butt plate, folds with the push of a button.

The stock folds all the way around past the trigger guard.

Folding the stock is as easy as pushing a button.

Installation is simple, though it requires the use of a Dremel. Users must first drill out the washers located at the rear of the MP40 then install the stock using a roll pin. The American Tactical rep told us the kit comes with instructions, and the company has also published an instructional video.

The rep told us the rear washer drills out without any trouble.

As we said in our review, the MP40’s weight makes the gun difficult to shoot for extended periods of time, so American Tactical’s new product can provide a more comfortable shooting experience.

The stock kit starts at $249.95, but it also includes a cold rolled steel magazine floor plate with a parkerized finish, a 4140 steel muzzle adapter with a ½ X 36 thread pitch, and a HDPR polyethylene thermoplastic magazine follower.

9mm AR-15 Adapter

American Tactical also featured their new 9mm AR-15 adapter. The kit fits into standard AR-15 lower receivers and uses Glock style double-stack magazines. The upper receiver, barrel, and bolt obviously have to be replaced as well, but American Tactical’s new product allows shooters to use their existing AR-15 lower if they want to move to a pistol-caliber carbine.

American Tactical’s new 9mm adapter is a great option for anyone looking to get into the pistol caliber carbine game.

The 9mm adapter starts at $169.95 and includes a ten-round magazine. Visit to learn more.

***Shop GunsAmerica for a ATI Guns***

About the author: Jordan Michaels has been reviewing firearm-related products for over four years and enjoying them for much longer. With family in Canada, he’s seen first hand how quickly the right to self-defense can be stripped from law-abiding citizens. He escaped that statist paradise at a young age, married a sixth-generation Texan, and currently lives in Waco. Follow him on Instagram @bornforgoodluck and email him at

{ 7 comments… add one }
  • GARY MOCK January 5, 2021, 10:04 pm


  • GARY MOCK December 30, 2020, 3:54 pm

    Do you sell the MP 40 9mm or the MP 22CAL.

  • Philip May 7, 2018, 2:42 pm

    Add $100 or so and purchase the HiPoint PCC in caliber of choice that seem to work well.

    • ejharb June 1, 2018, 7:29 am

      But a highpoint is not a mp40 “schmeisser!” Which drops a bunch of “holy sheisse! Is that a”cool points.and with that stock you have a sbr which adds $200 and paperwork for uncle sam.I hate the nfa!

  • wrangler5 May 7, 2018, 11:45 am

    Better check state and local laws, too. I believe some prohibit SBRs even if you have the ATF tax stamp.

  • Cymond May 7, 2018, 12:17 am

    I think I’ll get the $75 TorkMag Glock adapter, instead!
    Yes, you have to slightly modify the Glock magazines to work in the TorkMag, but the $100 price difference more than makes up for that.

  • Will Drider May 7, 2018, 12:13 am

    Since the ATI MP40 is a pistol with a 10 inch barrel: you would need to apply and receive NFA Short Barreled Rifle (SBR) Tax Stamp before adding the sholder stock. You might read the BATFE interpretation “Constructive Possession”. Having access to the parts without a Stamp can get you in trouble too.

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