The Gemtech GVAC upper receiver is chambered in 5.56x45mm NATO and uses a 16.1-inch barrel with a mid-length direct-impingement gas system. It includes a 15-inch free-float M-LOK handguard, Gemtech ETM flash hider, and bolt carrier group; the supplied listing specifies that a charging handle is not included.

Key Specifications

• The chambering is 5.56x45mm NATO for compatibility with the specified cartridge.
• The barrel measures 16.1 inches and features a GVAC profile, Armornite treatment, and 1:8 twist.
• The barrel uses 5R rifling and has 1/2×28 muzzle threads.
• The gas system is a mid-length pinned GVAC direct-impingement system with a low-profile 4140CM steel gas block.
• The upper receiver is made from 7075-T6 aluminum with a Type III hard-coat anodized finish, indexing marks, and M4 feed ramps.
• The handguard is a 15-inch Midwest Industries M-LOK free-float model with a continuous MIL-STD 1913 Picatinny top rail and integrated QD sling sockets.
• The handguard is constructed from 6061-T6 aluminum with a Type III hard-coat anodized finish.
• The muzzle device is a Gemtech ETM flash hider made from 4140CM steel.
• The included bolt carrier group uses a Carpenter 158 steel bolt and 8620 steel carrier with a chrome-lined interior and properly staked gas key.
• The supplied configuration includes a bolt carrier group and does not include a charging handle.

With its specified barrel profile, mid-length gas system, free-float M-LOK handguard, and included bolt carrier group, the GVAC upper provides a well-defined platform for users assembling a compatible 5.56x45mm NATO rifle configuration.