Alexander Arms UST17 18-inch Fluted AR-15 Upper w/ M-LOK

The Alexander Arms UST17 upper is an AR-15 upper assembly configured with an 18-inch fluted stainless barrel and an aluminum M-LOK handguard. The package includes an A2-style flash hider, a parts kit for converting a standard AR-15 lower, and two 10-round magazines. The assembly is described as using a blowback operating system in manufacturer materials.

Key Specifications

• The barrel measures 18 inches.
• The barrel is made of steel.
• The barrel finish is listed as stainless.
• The barrel is described as fluted.
• The barrel threading is listed as 1/2-28 RH.
• The handguard is an aluminum M-LOK style.
• The package includes two 10-round magazines.
• Includes a conversion parts kit with items such as a recoil cassette, magazine well insert, and magazine catch to fit most standard AR-15 lowers (lower conversion parts included).
• The upper is described as using a blowback operating system.

This upper assembly provides a straightforward, parts-inclusive option for shooters building or converting a standard AR-15 lower to the specified configuration. With a fluted stainless barrel and an aluminum M-LOK handguard, it is configured to serve as a durable, accessories-ready upper for range use and general shooting applications.