AR-15 Line

AR-15 6.8 SPC II 10.5" Pistol Builder Kit | M-LOK, SBA3 Brace, USA Made – Moriarti Armaments

Build your next AR-15 with the Moriarti Armaments AR-15 6.8 SPC II 10.5" Pistol Builder Kit. Designed for reliability, compact performance, and customization, this kit includes nearly everything needed to complete your AR-15 pistol build—excluding the 80% stripped lower receiver.

Featuring a 10.5-inch heavy-profile 6.8 SPC II barrel, free-float M-LOK handguard, and SBA3 adjustable stabilizing brace, this builder kit is ideal for shooters looking for a compact, hard-hitting AR platform. The carbine-length gas system delivers dependable cycling, while the forged 7075-T6 upper receiver and Mil-Spec components provide long-lasting durability.

Designed around the 6.8 SPC II chamber, this kit requires a 6.8 SPC II bolt, which is also compatible with .224 Valkyrie bolt assemblies, making future caliber conversions more convenient.

Whether you're building your first AR or adding another caliber to your collection, this USA-made kit delivers the quality, compatibility, and performance builders expect from Moriarti Armaments.

Features

Barrel

• Caliber: 6.8 SPC II
• Length: 10.5"
• Heavy Profile
• 4150 Chrome Moly Vanadium Steel
• Parkerized Finish
• Twist Rate: 1:10
• Thread Pitch: 5/8x24
• Carbine-Length Gas System
• .750" Gas Block Journal

Upper Assembly

• Forged 7075-T6 Flat Top Upper Receiver
• Hard Coat Anodized
• M4 Feed Ramps
• Forward Assist Installed
• Dust Cover Installed
• A2 Flash Hider
• Crush Washer Included

Handguard

• 10" Slim Free-Float M-LOK Rail
• Aircraft-Grade Aluminum
• Hard Coat Anodized
• Lightweight Design

Lower Build Kit

• Complete Mil-Spec Lower Parts Kit
• Mil-Spec Charging Handle
• SBA3 Adjustable Brace
• Mil-Spec Buffer Tube Assembly

Kit Includes

• Complete Upper Assembly
• 10.5" 6.8 SPC II Barrel
• Free-Float M-LOK Handguard
• Complete Lower Parts Kit
• SBA3 Adjustable Brace
• Buffer Tube Assembly
• Charging Handle

Does NOT Include

• 80% Stripped Lower Receiver

Why Choose a 10.5" 6.8 SPC II?

The 10.5-inch barrel offers a compact, maneuverable platform while maintaining the performance that has made 6.8 SPC II a popular choice among AR-15 enthusiasts. Paired with a carbine-length gas system and 1:10 twist, this configuration provides dependable reliability and broad ammunition compatibility.

An added advantage is compatibility with 6.8 SPC II / .224 Valkyrie bolts, making this platform a flexible option for builders planning future caliber changes.

Made in USA

All major components are manufactured in the USA using Mil-Spec standards for durability, compatibility, and dependable performance.

Important Information

• Ships unassembled.
• Compatible with most Mil-Spec AR-15 lower receivers.
• This builder kit is not an FFL item because the lower receiver is not included.
• Product images may vary slightly from the final configuration.

Frequently Asked Questions

Does this builder kit include the lower receiver?

No. This kit includes all major components needed to complete your build except the 80% stripped lower receiver.

Is this a complete AR-15 builder kit?

Yes. It includes the upper assembly, lower parts kit, SBA3 brace, buffer system, charging handle, and hardware needed to complete your build when paired with a compatible stripped lower receiver.

What bolt does this 6.8 SPC II kit require?

This kit requires a 6.8 SPC II bolt, which is also compatible with .224 Valkyrie. A standard 5.56 NATO bolt is not compatible.

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

Yes. The kit is designed to fit virtually all Mil-Spec AR-15 lower receivers.

What twist rate does the barrel use?

The barrel features a 1:10 twist rate, ideal for stabilizing a wide range of 6.8 SPC II bullet weights.

Is the handguard free-floating?

Yes. The included 10-inch M-LOK handguard is a lightweight free-float design manufactured from aircraft-grade aluminum.

Is the barrel threaded?

Yes. The barrel uses 5/8x24 threads, compatible with many muzzle devices designed for 6.8 SPC II.

Is this kit made in the USA?

Yes. The major components are manufactured in the USA using Mil-Spec standards for quality and compatibility.

Is the SBA3 brace included?

Yes. The kit includes an SBA3 adjustable stabilizing brace with a Mil-Spec buffer tube assembly.

Who is this builder kit best suited for?

This kit is ideal for builders looking to assemble a compact 6.8 SPC II AR-15 pistol using premium Mil-Spec components, with the added flexibility of using the same bolt face as .224 Valkyrie for future caliber options.