Engineered to maximize the flat-shooting performance of the 6mm ARC cartridge in a maneuverable footprint, this 12.5″ Ironclad barrel provides the ideal balance of compact length, velocity, and match-grade accuracy. Precision-machined from 4150 steel with straight fluting, it reduces overall front-end weight while significantly expanding surface area for rapid heat dissipation during sustained fire.

Equipped with a mid-length gas system, a 1:7.5 5R rifling profile, and an NTF-coated extension, this barrel delivers smooth cycling, balanced gas metering, and slick lockup reliability. To guarantee supreme feeding and extraction reliability, each barrel features a honed and polished chamber along with hand-polished feed ramps. Every production run undergoes 100% Quality Control (QC) inspection alongside Magnetic Particle Inspection (MPI), all wrapped in a heavy-duty Black Nitride finish for maximum bore life and corrosion resistance.

Key Highlights

• 6mm ARC Performance: Chambered specifically to harness high velocity 6mm ARC match loads out of a compact platform.
• 5R Rifling (1:7.5 Twist): Advanced 5R rifling optimizes bullet stabilization and velocity while reducing jacket deformation.
• Hand-Finished Precision: Honed and polished chamber combined with hand-polished feed ramps ensure effortless round feeding and positive extraction.
• 100% QC & MPI Inspected: Every barrel undergoes full 100% QC inspection and Magnetic Particle Inspection (MPI) to guarantee zero material defects.
• Straight Fluted Profile: Enhances barrel stiffness, dissipates heat faster, and shaves unnecessary weight.
• Mid-Length Gas System: reduces felt recoil for faster follow-up shots.
• NTF Coated Barrel Extension: reduce the friction coefficient when the bolt lugs rotate lock, and unlock into the extension.
• Dimpled Gas Journal: Factory-dimpled .750″ gas block journal guarantees perfect, slip-free gas block alignment.
• Duty-Grade Nitride Finish: Full Black Nitride (QPQ) finish resists carbon fouling, gas erosion, and severe weather.

Technical Specifications

Specification	Detail
Caliber	6mm ARC
Barrel Length	12.5 Inches
Weight	1lb 14oz
Material	4150 Steel
Profile / Contour	Straight Fluted
Twist Rate & Rifling	1:7.5 Twist, 5R Rifling
Chamber	Honed & Polished Chamber
Feed Ramps	Hand-Polished Feed Ramps
Gas System Length	Mid-Length
Gas Block Journal	.750″ (Factory Dimpled)
Barrel Extension Coating	NTF Coated
Muzzle Thread Pitch	5/8×24 TPI
Finish	Black Nitride (QPQ)
Quality Control & Testing	100% QC Inspected & Magnetic Particle Inspected (MPI)
SKU	STT-1836I-125B-6ARC-N