AR-57
AR-15/M16 upper or complete rifle firing 5.7×28mm from P90 magazines.
The AR-57, also called the AR Five Seven, is a firearm that can be purchased as a complete rifle or as an upper receiver for an AR-15 or M16. It fires 5.7×28mm ammunition from standard FN P90 magazines, which sit horizontally on top of the front handguard. Spent casings eject downward through the magazine well. To catch these casings, a user can modify a standard AR-15/M16 STANAG magazine by removing its internal parts, or attach a sheet metal brass catcher to the lower receiver. The design was originally created by Rhineland Arms and is now produced by AR57 LLC.
The upper receiver is a monolithic, lightweight unit that replaces the gas-tube system of a standard AR-15 with a straight blowback action. A Picatinny rail allows for mounting various scopes and accessories. A fully automatic version was marketed as a competitor to the FN P90 and other personal defense weapons. Suppressed variants are also offered. In 2019, during the crisis in Venezuela, defecting Venezuelan soldiers loyal to Juan Guaidó were photographed using an AR-57.
Quick Facts
- Origin
- United States
- Is Ranged
- Yes
- Service
- 2019–present
- Wars
- Venezuelan crisis
- Design Date
- 2008–2016
- Manufacturer
- Rhineland Arms (original), AR57 LLC
- Unit Cost
- US$1,099
- Production Date
- 2008–present
- Weight
- 7.45 lb (AR-57 PDW)
- Length
- 30 in (AR-57 PDW)
- Part Length
- 16 in (AR-57 PDW)
- Cartridge
- FN 5.7×28mm
Facts from the source article.
Lore & Background
The AR-57 was originally designed by Rhineland Arms and later produced by AR57 LLC. The PDW upper receiver is a new design that blends the AR-15/M16 lower with a lightweight, monolithic upper receiver system chambered in 5.7×28mm. The complete rifle is supplied with two 50-round P90 magazines. The magazines mount horizontally on top of the front handguard, and brass ejects through the magazine well. AR-15/M16-based STANAG magazines can be used to catch spent casings by removing the feed lips, spring, and follower; sheet metal brass catchers can also be used on the lower. Various scopes and other accessories can be mounted on the picatinny rail. Unlike the standard AR-15 configuration which uses a gas-tube system, the AR-57 cycles via straight blowback. A fully automatic version exists and was marketed as a competitor to the P90 and other personal defense weapons. Suppressed versions are also available.
Reader's Guide
The AR-57 occupies a unique niche as a hybrid design that adapts the ubiquitous AR-15/M16 platform to fire the 5.7×28mm cartridge from P90 magazines. Its straight blowback operation and top-mounted magazine set it apart from conventional AR-15 variants, offering a compact, lightweight personal defense weapon option. The availability of a fully automatic version positioned it as a competitor to the FN P90 and similar PDWs. The design's flexibility—available as an upper receiver for existing AR-15/M16 lowers or as a complete rifle—allowed users to convert standard rifles without purchasing an entirely new firearm. Suppressed versions further extended its utility. The AR-57 saw documented use during the crisis in Venezuela in 2019, where Venezuelan soldiers who defected to Juan Guaidó were photographed using the weapon, indicating its adoption in real-world conflict settings beyond its intended PDW role.
Did You Know?
- The AR-57 is also known as the AR Five Seven.
- It was originally designed by Rhineland Arms but produced by AR57 LLC.
- The magazines mount horizontally on top of the front handguard, with brass ejecting through the magazine well.
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