12.5" .338 ARC AR-15 Pistol Barrel – 1:8 Twist

Barrels

AR-15 .338 ARC 12.5" Pistol Barrel | 1:8 Twist | Pistol Gas | 5/8-24

Build a compact .338 ARC AR-15 with the Moriarti 12.5" .338 ARC Pistol Barrel, featuring a 1:8 twist rate and pistol-length gas system. This configuration provides more barrel length than ultra-compact .338 ARC setups while maintaining a short, maneuverable platform.

Manufactured from durable 4150 CrMoV steel, the barrel features a medium profile and protective nitride finish for a practical combination of strength, durability, and corrosion resistance. The muzzle is threaded 5/8-24 for appropriately compatible muzzle devices and suppressor mounting systems.

The 12.5-inch barrel length occupies a useful middle ground between Moriarti's shorter fast-twist .338 ARC barrels and full-length rifle configurations. Its 1:8 twist provides a different barrel option for customers selecting a .338 ARC configuration based on ammunition, projectile, barrel length, and intended application.

Whether you're putting together a compact .338 ARC pistol or an appropriately registered SBR configuration, this 12.5" .338 ARC barrel provides a purpose-built AR-15 foundation for the increasingly popular .338 ARC cartridge.

Specifications

Key Features

• 12.5" .338 ARC AR-15 barrel
• 1:8 twist rate
• Pistol-length gas system
• Medium barrel profile
• 5/8-24 muzzle threads
• 4150 CrMoV barrel steel
• Durable nitride finish
• Compact intermediate-length .338 ARC configuration
• Threaded for appropriately compatible muzzle devices and suppressor mounts

Suppressor Compatibility

The 5/8-24 thread specification does not mean every .338-caliber suppressor is compatible. Verify that the suppressor manufacturer specifically approves the suppressor and mounting system for the cartridge, barrel length, ammunition, and firearm configuration.

What is the advantage of a 12.5" .338 ARC barrel?

A 12.5" .338 ARC barrel provides an intermediate configuration between ultra-short pistol barrels and longer rifle barrels. This Moriarti barrel combines its 12.5" length with a 1:8 twist and pistol-length gas system, making it an option for customers who want a compact .338 ARC platform without moving to the shortest available barrel lengths.