CMMG Carbine Length Gas Tube with Roll Pin

The CMMG Carbine Length Gas Tube with Roll Pin is a critical direct impingement system component engineered for AR-platform rifles configured in carbine-length gas port setup. This gas tube assembly channels high-pressure combustion gases from the barrel back to the bolt carrier group, cycling the action and enabling semi-automatic fire. The included roll pin secures the assembly to the upper receiver, ensuring reliable function under sustained fire and field conditions.

Carbine-length gas systems—shorter than rifle or mid-length variants—deliver faster bolt carrier velocity and cyclic rates. This characteristic makes them favored for shorter barrel AR builds (14.5" to 16" ranges), where gas port pressure must be optimized to reliably cycle lighter bolt carrier assemblies while managing recoil impulse. The CMMG tube measures 5.1 inches, fitting standard carbine-length specification envelopes. Weighing only 0.07 pounds, the component adds minimal mass while maintaining the structural rigidity necessary for thousands of firing cycles. Proper gas tube selection directly impacts reliability: mismatched lengths or damaged tubes cause short-stroking, failure to feed, and ejection inconsistencies that compromise combat readiness.

This replacement part serves operators building or maintaining patrol rifles, training carbines, and duty ARs where original tubes have corroded, dented, or failed under use. Issued replacements after damage inspection, or purchased as preventive maintenance spares, carbine-length gas tubes are essential inventory for armories and serious shooters maintaining multiple platforms. CMMG's manufacturing reputation within the AR community reflects decades of direct impingement and piston system expertise.

Gas tube compatibility is non-negotiable—selecting the correct length ensures your rifle functions as designed. Carbine-length systems are not interchangeable with mid-length or rifle-length tubes. Verify your upper receiver's gas port location before purchase to confirm carbine-length is your requirement. Installation requires minimal tools and basic AR knowledge; the roll pin retains the tube during disassembly and reassembly.

Upgrade or repair your carbine's gas system with a genuine CMMG component trusted by law enforcement, military, and competitive shooters. Shop TacticalSurplusUSA for OEM and aftermarket AR parts that keep your rifle field-ready.