AR-57 AR57 ULT Upper | 5.7x28mm | 16in Barrel

The AR-57 ULT Upper Assembly is an AR-platform upper configured for the 5.7x28mm cartridge and a 16 inch barrel. It is presented as a lightweight tactical upper forged as a monobloc from 7075-series aluminum with a 1:9 twist barrel and steel bolt-carrier components. The assembly is suited for range-oriented shooting and competition use where the 5.7x28mm cartridge is desired.

Product Specifications

• The manufacturer is AR-57 (Ar Five Seven Center).
• The model is listed as AR57 ULT Upper Assembly.
• The caliber is 5.7x28mm.
• The barrel measures 16 inches.
• The barrel twist rate is 1:9.
• The upper is described as forged from 1 7075 T6 Monobloc Aluminum.
• The bolt carrier and related components are described as 8620 steel alloy.
• The finish is reported as black Melonite-style treatment in manufacturer text.
• The assembly is identified for the AR15 Uppers category.
• The product UPC is 051497297985.

This upper provides an OEM-style option to install a 5.7x28mm configuration on a compatible AR-platform lower for range shooting and match-style applications. It pairs lightweight monobloc aluminum construction with steel bolt-carrier components to balance weight and durability. For shooters seeking a factory-style 5.7x28mm upper for training or competition, the AR57 ULT presents a straightforward solution built around known component materials and a 1:9 twist barrel.