Davidson Defense Showstopper 5.5-inch 1:16 10MM AR-15 Freefloat M-Lok Handguard Pistol Upper Build Kit

Showstopper 5.5-Inch 1-16 10mm AR-15 Freefloat M-LOK Handguard Pistol Upper Build Kit

This is an AR-15 upper build kit chambered in 10mm Auto, built around a 5.5-inch medium profile steel barrel with a black nitride finish, a 1-16 twist rate, and a 5-8x24 thread pitch. The billet 6061 aluminum AR-15 pistol caliber upper receiver anchors the front end, a purpose-built receiver for the pistol caliber AR platform. The 4-inch freefloat aluminum M-LOK handguard with a full-length top Picatinny rail covers the compact forend. A Pershing steel flash can in black at 5-8x24 closes out the muzzle end. This upper operates on a direct blowback system and does not include a gas tube or gas block. BCG and charging handle are not included.

Key Features

• 10mm Auto chambering, 5.5-inch medium profile steel barrel, black nitride finish
• 1-16 twist rate, 5-8x24 thread pitch
• Direct blowback operation, no gas tube or gas block
• Billet 6061 aluminum AR-15 pistol caliber upper receiver
• 4-inch freefloat aluminum M-LOK handguard, full-length top Picatinny rail, no anti-rotation tabs
• Pershing steel flash can, black, 5-8x24 thread pitch
• Black 5-8-inch crush washer

Perfect For

• AR-15 pistol builders sourcing a 10mm upper assembly without BCG or charging handle
• Shooters adding a compact 5.5-inch direct blowback 10mm upper to an existing lower with a compatible blowback bolt and charging handle on hand
• Builders who want a billet pistol caliber upper receiver and full-length top rail M-LOK handguard in one compact 10mm upper kit

Upper Receiver and Barrel

The billet 6061 aluminum AR-15 pistol caliber upper receiver forms the core of the front end, a purpose-built unit designed around the pistol caliber AR platform rather than a standard 5.56 upper receiver. The 5.5-inch medium profile steel barrel brings a black nitride finish and a 1-16 twist rate to the 10mm Auto chamber, threaded at 5-8x24. This upper operates on a direct blowback system, which means there is no gas tube or gas block on this upper. The bolt carrier group drives the blowback cycling function directly, so no gas system components are present or required. The 4-inch freefloat aluminum M-LOK handguard surrounds the barrel along the compact forend with a full-length top Picatinny rail running the entire length of the handguard for optics and accessory mounting, and M-LOK slots along the remaining handguard surfaces for additional accessory attachment. The handguard does not include anti-rotation tabs, a design characteristic of this specific unit.

Muzzle Device

The Pershing steel flash can in black threads onto the 5-8x24 muzzle end of the barrel and closes out the front of this compact pistol-length upper with a flash can profile suited to the 10mm bore diameter at this thread pitch. The included black 5-8-inch crush washer seats at the barrel shoulder and completes the muzzle hardware for this kit.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. BCG and charging handle are not included.