AR-15 Line

AR-15 .338 ARC 10.5" Pistol Kit | 1:5 Twist | SBA3 Brace | 6.5 Grendel BCG

The Moriarti 10.5" .338 ARC AR-15 Pistol Kit is built around a compact 10.5-inch .338 ARC barrel with a fast 1:5 twist, paired with an SBA3 pistol brace and a 6.5 Grendel-pattern bolt carrier group.

Designed for a compact .338 ARC configuration, the barrel features 5/8x24 muzzle threads for compatible muzzle devices and suppressor mounting systems. The fast-twist barrel and short overall setup make this kit especially appealing to shooters interested in heavy-projectile, subsonic, and suppressor-oriented .338 ARC applications.

The included SBA3 brace gives the kit a familiar adjustable pistol configuration, while the 6.5 Grendel-pattern BCG provides the proper bolt-face setup for .338 ARC. The kit includes the listed upper and lower-component groups needed for the configuration while excluding the lower receiver.

For shooters moving beyond 300 Blackout or adding a new large-projectile AR-15 caliber, this 10.5" .338 ARC pistol kit offers a compact package with modern .338 ARC performance potential.

Key Features

• Caliber: .338 ARC
• Platform: AR-15
• Barrel Length: 10.5"
• Twist Rate: 1:5
• Muzzle Thread: 5/8x24
• BCG: 6.5 Grendel-pattern BCG
• Brace: SBA3 Adjustable Pistol Brace
• Configuration: AR-15 pistol kit
• Lower Receiver: Not included
• Threaded Muzzle: For compatible muzzle devices and suppressor mounts
• Suppressor Compatibility: Verify suppressor rating, barrel-length requirements, ammunition, and mounting specifications

Important

This kit does not include a lower receiver. Exact components included should be determined by the individual product configuration and the parts shown/listed on the product page.

Why .338 ARC?

The attraction of .338 ARC is its ability to bring heavy .338-caliber projectile capability to the AR-15-size platform. For customers already familiar with 300 Blackout, .338 ARC represents another option for compact configurations, particularly where heavy bullets and suppressor-oriented applications are priorities.

Is a 10.5" .338 ARC good for suppressed use?

A 10.5" .338 ARC can be an attractive compact platform for shooters interested in suppressed and heavy-projectile applications. This Moriarti configuration features a fast 1:5 twist barrel and 5/8x24 muzzle threads for compatible mounting systems. Suppressor ratings vary, however, so always verify that the specific suppressor is approved by its manufacturer for .338 ARC, the applicable barrel length, ammunition, and mounting configuration.