AR57 Pistol

The AR57 pistol upper for sale, also known as the AR Five-Seven , is available as either an upper receiver for the AR-15/M16 rifle or a complete rifle, firing 5.7×28mm rounds from standard FN P90 magazines. It was designed by AR57 LLC and is currently produced by AR57 of Kent, Washington, USA. The AR57 pistol PDW Upper is a new design on AR-15/M16 rifles, blending the AR-15/M16 lower with a lightweight, monolithic upper receiver system chambered in FN 5.7×28mm. This model is also sold as a complete rifle, supplied with two 50-round P90 magazines. The magazines mount horizontally on top of the front handguard, with brass ejecting through the magazine well. Hollow AR-15 magazines can be used to catch spent casings.

Unlike the standard AR-15 configuration which uses a gas-tube system, the AR-57 cycles via straight blowback. A full-auto version exists marketed as a competitor to the P90 and other personal defense weapons.

AR57 Pistol Specifications

The AR57 is an upper receiver for the AR-15 platform chambered in the 5.7x28mm, it was designed by the eponymous AR57 LLC. The AR57 uses a P90 magazine. Spring pressure pushes the rounds out like a traditional magazine. However the feed lips have a ramp, think of a multi-level car garage. So the cartridges sort of drift 90 degrees down the ramps to line up with the bore and chamber.

The handguard is rather narrow so while you could possibly install a flash hider I do not think it would be a good idea. Remember the AR pistol with the muzzle brake under the handguard? Only a suppressor or even a faux suppressor would be safe to use with this upper receiver. Obviously, that is not an issue for the 12″ which the muzzle protrudes just past the end of the handguard. And the 16″ barreled version has a rather long barrel past the handguard.

ar57 pistol upper for sale

Yes, we chose this option however trying to remove the suppressor can be difficult. As you can see in the photos above, there is not a lot of room to grab onto the sides.

We had to use a flat head screwdriver to turn the end cap. Only because of the shape and design of the end cap was I able to do that. If you had a different can be rated for 5.7x28mm, like the Bowers USS 22 suppressor there is nothing to grab onto and it would be very difficult to remove it. The Bowers USS 22 does have interchangeable threaded endcaps so it would not be a huge loss to leave a dedicated end cap on the AR57 if you were to use that suppressor.