AR Five Seven: 5.7×28mm AR Upper

Sneak peek of AR57

AR57 PDW Upper on Standard AR Lower

AR57 PDW Upper on Standard AR Lower

The Firearm Blog has the goods:

The AR Five Seven is a one piece 5.7×28mm upper that attaches to a AR-15 lower and uses the 50 round FN P90 magazines.

Also see his earlier post on the subject, which includes a reader comment about turning an AR magazine body into a brass catcher.


  1. That’s pretty cool, but am I right in thinking there’s no foregrip and thus it’s going to be fairly hard to use the stock? I mean, you have the stock against your shoulder, your eye up to the sights, where to you put your other hand to steady the aim? Perhaps some kind of plastic barrel shroud would be good. Before they’re banned. Again.

    1. The whole piece around the barrel is essentially a barrel shroud, you would hold it like a regular rifle. Notice the rails, you could add a forward grip if you so choose.

  2. is that a straight barrel with no shroud or muzzle break? Or is the muzzle break internally surrounding the whole end of the barrel like the WA2000?

  3. Come on are you guys that thick?
    It has a quad rail, put a forward grip on it. And that is the gemtech suppressor on the one in the picture.

  4. Hello there guys,

    I have a COMPLETE AR57 UPPER. But, I do not want to use my lower receivers out of my other AR15’s. So, WHERE CAN I GET
    A COMPLETE LOWER RECEIVER that is MARKED “AR57″ Five Seven ”

    Try get a close look at the complete AR57 Rifle and you will notice that the complete lower receiver is nicely marked AR57
    made by a certain Aero Precision Inc of Washington. It even has a pistol grip that is likewise marked AR57.

    But can it be bought as a separate unit ? I mean the complete lower receiver marked AR57?

    PLEASE PLEASE LET ME KNOW if you have an answer.


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