This listing is the SIG Sauer MCX 16-inch 5.56 NATO complete upper conversion kit in black with a tapered bolt lug. This listing is for this 16-inch 5.56 NATO TAP upper kit only.

The kit puts an MCX short-stroke piston upper on a compatible AR-15 / M400 lower. The 16-inch 5.56 NATO barrel uses a 1:7 twist and 1/2-28 muzzle threads. A tapered bolt lug is used. The recoil system is internal, so a conventional rifle buffer tube is not required. An aluminum M-LOK handguard and a hard-coat anodized black finish are fitted. The kit includes the complete 16-inch upper assembly, an MCX-to-M400 lower adapter, an X-Fold 1913 stock adapter, a 90-degree muzzle adapter, a SIG Matchlite DUO two-stage trigger kit, and a 1913 low-profile QD socket.

This listing is the SIG Sauer MCX black 16-inch 5.56 NATO TAP conversion upper only.

• Manufacturer: SIG Sauer — MCX 16 in 5.56 NATO TAP conversion upper, SKU WUAMCX-16B-556-BLK-TAP, UPC 798681579402
• Caliber / barrel: 5.56 NATO; 16 in; 1:7 twist; 1/2-28; tapered bolt lug
• System: short-stroke piston; internal recoil; aluminum M-LOK handguard; black
• Kit: complete upper; M400 lower adapter; X-Fold stock adapter; 90-degree muzzle adapter; Matchlite DUO trigger; 1913 QD socket
• This listing: this 16-inch 5.56 NATO TAP MCX upper kit only
• This item is restricted to LE / MIL / first responders only.