10.5" .338 ARC AR-15 Pistol Barrel – 1:5 Twist

Barrels

AR-15 .338 ARC 10.5" Pistol Barrel | 1:5 Twist | Pistol Gas | 5/8-24

Build a compact .338 ARC AR-15 around the Moriarti 10.5" .338 ARC Pistol Barrel. Featuring a fast 1:5 twist rate and pistol-length gas system, this barrel is designed for short .338 ARC configurations where compact dimensions and heavy-projectile capability are priorities.

The barrel is manufactured from durable 4150 CrMoV steel with a medium profile and protective nitride finish. A .750" gas block journal provides compatibility with appropriately sized gas blocks, while the muzzle is threaded 5/8-24 for compatible muzzle devices and suppressor mounting systems.

At 10.5 inches, this barrel provides a practical middle ground between ultra-short .338 ARC configurations and full-length rifle barrels. The combination of a short barrel and 1:5 twist makes it particularly relevant for customers researching compact, heavy-projectile and suppressor-oriented .338 ARC platforms.

For shooters moving beyond 300 Blackout or adding .338 ARC to an AR-15 collection, this 10.5" .338 ARC barrel provides a purpose-built foundation for a compact pistol or properly registered SBR configuration.

Specifications

Key Features

• 10.5" .338 ARC AR-15 barrel
• Fast 1:5 twist
• Pistol-length gas system
• .750" gas block journal
• Medium barrel profile
• 5/8-24 threaded muzzle
• 4150 CrMoV construction
• Durable nitride finish
• Purpose-built for compact .338 ARC configurations
• Threaded for appropriately compatible muzzle devices and suppressor mounts

Suppressor Compatibility

The 5/8-24 muzzle thread does not automatically make every .338 suppressor compatible. The suppressor and mounting system must be manufacturer-rated for the cartridge, barrel length, ammunition, and firearm configuration.

What gas system does a 10.5" .338 ARC barrel use?

This Moriarti 10.5" .338 ARC barrel uses a pistol-length gas system with a .750" gas block journal. Gas-system specifications are especially important when selecting components for a short-barreled AR-15 configuration, so the gas block, gas tube, ammunition, and other components should be matched to the barrel manufacturer's specifications.