AR-15 Carbine Length Gas Tube

Carbine Gas Tube

This United Defense gas tube is a replacement or build part for AR-15 rifles that run a carbine-length gas system. On a direct impingement AR-15, the gas tube carries propellant gas from the port in the barrel back into the upper receiver, where it drives the bolt carrier and cycles the action. Builders assembling a new upper, and owners replacing a bent, worn or fouled tube, can use it to put the gas system back to spec.

Features

• Carbine-Length Gas System — Sized for barrels with a carbine-length gas port, the shortest of the common AR-15 gas system lengths.
• Direct Impingement Design — Routes gas straight from the gas block to the bolt carrier key, the way the standard AR-15 operates.
• Pre-Drilled Roll Pin Hole — A cross hole at the front end accepts the gas tube roll pin that locks the tube into the gas block.
• Formed Offset Bend — A bend along the length steps the tube from the gas block's height down to line up with the gas tube hole in the upper receiver.
• Open Tube Profile — A straight, smooth bore runs the full length so gas can travel without obstruction.
• Bright Metal Finish — The tube has a plain silver finish, as shown in the product photograph.
• Standard AR-15 Interface — It follows the conventional AR-15 layout, so it installs with the usual gas block and upper receiver setup.

Fit And Installation

Gas tube length has to match the gas system length of your barrel, so check that your barrel uses a carbine-length port before ordering. The front end slides into the gas block and is retained by a roll pin through the drilled hole. The rear end passes through the barrel nut and into the upper receiver, where it feeds the bolt carrier key. The tube is sold on its own; a gas block and roll pin are not shown as included.