.338 ARC Upper

Moriarti AR-15 .338 ARC 10.5" Upper Assembly | M-LOK | A2 Flash Hider

Experience the superior performance of the Moriarti AR-15 .338 ARC 10.5" Upper Assembly, built for precision, modularity, and reliability in compact AR-15 pistol platforms. Whether you're looking for a tactical upgrade or a hunting companion, this upper is engineered to deliver next-level ballistic performance in a compact design.

Key Features:

Barrel

• Length: 10.5"

• Chamber: .338 ARC

• Twist Rate: 1:5 (optimized for heavy grain bullets)

• Material: 4150 Chrome Moly Vanadium

• Finish: Nitride

• Thread Pitch: 5/8x24

• Profile: Government

• Muzzle Device: A2 Flash Hider – reduces flash and recoil for improved control and low-light shooting

Gas System

• Pistol-length gas system for reliable cycling

• Steel low-profile gas block

Upper Receiver

• A3 flat-top design

• 7075-T6 aluminum forged construction

• Black hardcoat anodized (mil-spec)

• Includes forward assist and dust cover

• Ideal platform for optics and accessories

Handguard

• 10" Super Slim Free Float M-LOK Rail

• Lightweight and ergonomic

• M-LOK slots for modular accessory attachment

• Free-float design enhances accuracy

Perfect Pairings

• Match it with our Moriarti AR-15 6.5 Grendel BCG

• Complete your build with Moriarti Custom Cerakote Builder Sets

Note: Bolt Carrier Group (BCG) and Charging Handle are not included but can be added separately.

Made in the USA by Moriarti Armaments – Precision meets innovation.

Frequently Asked Questions

What is the .338 ARC designed for?

The .338 ARC was developed for shooters seeking a cartridge that performs efficiently from compact AR-15 platforms while supporting heavier projectiles than traditional intermediate calibers.

Is this a complete upper assembly?

Yes. This upper includes the assembled upper receiver, barrel, gas system, handguard, and A2 flash hider. The Bolt Carrier Group and Charging Handle are sold separately unless otherwise specified.

Is this upper suppressor ready?

Yes. The barrel features 5/8x24 muzzle threads, making it compatible with many suppressor mounting systems and muzzle devices.

What bolt does a .338 ARC upper require?

The .338 ARC uses a 6.5 Grendel / .338 ARC compatible bolt, which shares the same bolt face. A standard 5.56 NATO bolt is not compatible.

What twist rate does this barrel use?

The barrel features a 1:5 twist rate, designed to stabilize the heavier projectiles commonly used with the .338 ARC cartridge.

Is the handguard free-floating?

Yes. The included 10-inch M-LOK handguard is a lightweight free-float design that enhances accuracy while providing ample space for accessories.

Is this upper compatible with Mil-Spec AR-15 lowers?

Yes. It is designed to work with virtually all Mil-Spec AR-15 lower receivers.

Can this upper be used for hunting?

The .338 ARC has become increasingly popular among hunters looking for a compact AR-15 platform capable of launching heavier bullets. Always verify local hunting regulations before use.

Is this upper made in the USA?

Yes. The Moriarti .338 ARC Upper Assembly is manufactured in the USA using premium materials and Mil-Spec manufacturing standards.

Who is this upper best suited for?

This upper is ideal for shooters building a compact, suppressor-ready AR-15, hunters interested in the growing .338 ARC cartridge, and enthusiasts looking to expand their Micro AR collection with a modern, high-performance caliber.

Images may not be an exact representation of the product.