Masterpiece Arms MAC-10 in 5.7x28mm

A keen-eyed reader noticed that Masterpiece Arms have listed on their website a new MPA pistol chambered in 5.7x28mm. To accommodate the 30 round 5.7mm magazine (the same magazine used by the FN pistols?), they have a redesigned grip, which looks a lot more ergonomic than the aweful MAC-10 grip.

The pistol features a picatinny rail, a 5″ barrel threaded with a muzzle brake and a side-mounted cocking handle. The MSRP is $599.

[ Many thanks to Aaron for emailing us the info. ]

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Samopal


    • Woodroez

      A good question! My experience with an MPA9mm was that they had kinda bad muzzle flip, so 5.7x28mm might help mitigate that factor in this top-heavy, direct-blowback pistol.

      This will also be, as far as I know, the cheapest 5.7mm pistol available, and with a factory threaded barrel!

      Still, a weird move on their part. If they’re going to screw around this much with the MAC template, they had might as well make the 9mm and .45 models accept Glock mags.

      Steve, here’s a Youtube video that MPA released about this gun.

      • noob

        Would it be legal for Class III permit holders to pay the tax stamp and convert a transferrable full auto mac to 5.7mm? as in, would this be legal for civilians to own in full auto 5.7mm configuration?

        if so, you get something like a p90 or mp7 except it only holds 20 rounds.

      • mike

        Class III permit holders could do that after paying the tax stamp, but then the ATF could stop by unannounced to inspect the new configuration. A better option might be to convert their transferable full auto mac to .380, since .380s are exempt from the random inspection clause of the Class III Permit.

      • Other Steve

        Mike: You’re going to want to recheck all that info. As it’s almost ALL wrong. Title II weapon / tax stamp owners are NEVER subject to an inspection.

        SOTs can do whatever they damn well please for the most part (on a Form2).

        The ATF never stops by unannounced.

        Transferable machine guns are not restricted in caliber changes explicitly. Only hear-say on this. There are PLENTY of M16 owners with 22 uppers, 9mm, 300blk, etc.

      • Woodroez, we have built several prototypes of our MPA930 (9mm) to accept glock mags. Just have not decided to offer it to the public. Had lots of interest in this design concept. Just not sure how it will sell. Also, the 5.7 was in response to requests for a higher velocity platform than our 9mm and 45 acp models. The 5700sst will be a 16″ carbine and should be out in the next several weeks. We are using ER Shaw barrels on both the 5″ and 16″ models. Accuracy is quite nice.

  • Griff

    @ samopal Why not?

    • Samopal

      I guess I can see people buying this because it’s half the price of a Five-seveN…but it’s just weird. As far as I know there isn’t a huge civilian market for niche AP cartridges in retro semiautomatic machine-pistol variants.

  • Brian P.

    That’s interesting. This must be something they just announced or something, because I was just browsing MPA’s website last week, I believe.

  • Lance

    Coll redesign but id prefer standard 9mm or .45Auto over weak 5.7mm loads.

    • hojo

      In terms of muzzle energy, 5.7 x 28 and .45 acp are pretty close together. It’s the old small and fast versus big and slow. If you’re sure you’re firing at an unarmored target that’s pretty close, big and slow wins by delivering all it’s energy into the target. If there’s a car door, or light body armor in the way, or you’re firing at something further away (preferably not with a mac-10), small and fast wins, although clearly over-penetration becomes a risk. But weak? No.

      • Other Steve

        I agree mostly, it’s just that…

        The 5.7 vs anything else arugment gets a little messed up if you’re talking civilian or mil. Mil gets the good ammo, civs do not. A civilian 5.7 makes NO sense to me, but that’s just my opinion. The P90 is a very cool little gun, but given the option to chamber on it a different caliber I would absolutely.

        If you’re a civilian a defeating body armor is a main factor in your gun purchase, well, you’re in a different mindset than I am.

    • hojo

      Well, sure, if you want to be practical…

  • Komrad

    could an MPA upper be put on a NFA registered full-auto MAC-10? If so, it might be a good fit for submachinegun competition, but I suppose it would have a pretty high rate of fire still.

    There might be a market for this for countries that can’t afford an HK MP7 or FN P90 but require a PDW type weapon for protecting official VIPs. I wouldn’t bet any money on it as I have no experience in that field, however.

  • Spiros-Hellas

    I guess this is going to be a huge success in Mexico…

    • Yup. My first thought was that thing will be popular as a “mata policia” in places like Juarez.

  • hojo

    I’m impressed they were able to find a way to make a mac-10 even uglier.

    • Other Steve

      It’s taken years of design and re-design, but they have achieved their goal. Congrats!

  • mosinman

    wow this is kinda cool, i like the fact that its chambered in a new-ish round and its kinda cheap, i think 5.7 has its merrits but if i wanted a pistol id chose one in .45 just because i like it. this would be a good alternative for someone who cant afford a ps-90 or whatever

    • Other Steve

      Yea, that’s what I was thinking, if you already own a couple 5.7mm guns and are looking for another, then this thing might make sense.

  • Mu

    As the article said they had to redesign the grip to take FN magazines, I doubt you could make the upper fit on the MAC 10 base. Now, if you have a registered sear for a MAC 10 and it fits …

  • Mike

    The 5.7x28mm is a nifty little cartridge. While it may not have “knokdown power” and civilians may not be able to get “armor piercing” military/le ammo, nonetheless, it looks like a cool and affordable plinker in caliber, and the weapon will take more abuse than FN’s products. I think it would be great for “zombie’ style, any gun matches. or just to have fun with. Is it a stopper? No. Is it a varmit gun? No. Is It a survival gun? No. Is it a CCW? No. Is it for 3Gun? No. Is it for hunting? No. Is it for personal defense? No. Is it for fun? YES!

    • Other Steve

      “affordable plinker”

      Eh? .40-.50 per round is plinker? Oh. I’m apparently cheap then.

      • Mike

        LOL…The weapon not the ammo. If you want to shoot 5.7x28mm, this is a cheap way.

  • Valorius

    Fired from a FsN pistol, the Elite Ammo S4M round hits a velocity of 2500fps at the muzzle, for over 350fpe of energy. This is obviously many times more powerful than any .22 mag round fired by any pistol.

    The same Elite S4M round will penetrate in excess of 30 layers of kevlar with ease, and was independently reviewed by Brassfetcher ballistic labs.

    In it’s summary, Brassfetcher stated outright that the Elite S4M round is shot for shot slightly more terminally effective than Federal Hydrashok 230gr JHP ammunition.

    This same elite round has significantly less recoil than 9mm range plinking ammo when fired from a typical service pistol.

    And the FsN pistol can hold 30rds.

    Anyone that thinks this round and pistol combo are a gimmick, or over-hyped, is very poorly informed.

  • 45s rule

    comparing the 5.7x28mm to a 45 ACP is ridiculous come back in 115 years when the 5.7x28mm has been used in two world wars and countiless minor conflicts world wide. The problem that wll firsta rise is the 5,8mm is not a poular cal/cartridge in militaries world wide and will never be carreid nor used to such an extent as the 45 ACP. Then comparing a armor piercing round to a precut hoolow point bullet that wighes almost 200 grains more is ridiculus as AP rounds tend to do nthing but over penetrate human flesh. In fact actaul results aginst living tissue for the 5.8 mm is sorely lacking and will be 110+ years for now simply becuase its not what its cracked up to be. the round is expensive hard to find and hard to reload plus the only thing its supposed to e able to do is go through kevlar you know that bullet proof stuff that was invented in 1965 by Du-pont and tested in later taht decade for military vests and used commercialy in tires and fishing klines in teh 1970s…kevlar is thick,heavy and out dated as a ballsitic vast material so why is everyone yelling about a 5.7mm can defeat it…I have seen slow 9mm defeat vest of Kevlar IIIA ratings. really get a life and when a few billion rounds ahve been fired over a century and in world wide wars come back and then tell em about the 5.7×28 becuase now the average American cannot afford a pistol or carbine in that caliber.

  • Benjamint_Tanklin

    Despite the obtuse looking grip I picked up one of these in a rifle format at a gun show recently.

    The gun is quite accurate which is unsurprising given the barrel length.
    With a stock and a forward grip the gun handles like a dream and given the more compact dimensions of the rifle (thanks to the smaller magazine) I would love one as an SBR.

    It’s unfortunate that 5.7 ammo is kind of rare and very pricey now, especially since there is a reasonably priced platform that can handle the round quite well.