Pistol Length

AR-15 5.56 NATO 6" Modular Pistol Upper Assembly | Hybrid MLOK | A2 Flash Hider

Upgrade your AR-15 build with the Moriarti Arms 6" 5.56 NATO Modular Pistol Upper Assembly—engineered for shooters who demand a compact, accurate, and highly maneuverable platform. Featuring a premium 4150 CMV barrel with a 1:7 twist, this upper is designed to stabilize common 5.56 NATO ammunition and deliver excellent performance in a compact pistol configuration.

The 6" barrel is finished in QPQ nitride for exceptional corrosion resistance and durability, threaded 1/2x28 for broad compatibility with muzzle brakes, comps, suppressors, and included with an A2 flash hider. A forged 7075-T6 A3 flat-top upper receiver provides strength and precision alignment, while the 5.5" Hybrid MLOK handguard offers lightweight modularity for lights, grips, lasers, and more.

A .750 low-profile gas block and micro-length gas system ensure smooth cycling and reliability in short-barrel applications. This upper is ideal for compact AR-15 pistol builds, CQB-style setups, tactical training, and range fun—all backed by Moriarti Arms quality craftsmanship.

Key Features

• Caliber: 5.56 NATO (compatible with .223 Rem)

• Barrel: 6" 4150 CMV medium profile, QPQ nitride finish

• Twist Rate: 1:7 for optimal stability with a wide range of 5.56 loads

• Thread Pitch: 1/2x28

• Muzzle Device: A2 flash hider with crush washer

• Feed Ramps: M4 feed ramps for reliable feeding

• Upper Receiver: 7075-T6 forged aluminum, A3 flat top, hardcoat anodized

• Gas System: Micro-length

• Gas Block: .750 low-profile steel, hardcoat anodized

• Handguard: 5.5" slim Hybrid MLOK free-float rail

• Compatibility: Fits virtually all standard AR-15 lowers; BCG & CH optional add-ons

• Note: Images may slightly vary depending on rail inventory

  BCG and CH are not included.