The Carbine Length Gas Tube w/ Pin is a replacement or build component for AR-15 carbine-length gas systems. It meters propellant gas from the barrel port to the gas key on the bolt carrier group.
This gas tube fits carbine-length gas systems, the most common configuration on 14.5- to 16-inch AR-15 barrels. It installs between the gas block and upper receiver.
Whether you are replacing a damaged tube or finishing a new upper, the correct gas tube length matters. Carbine, mid-length, and rifle gas systems each require a different tube.
Key Facts
Product Name: Carbine Length Gas Tube w/ Pin
SKU: WS-CAR-GT
Gas System: Carbine length
Platform: AR-15
How Carbine Length Gas Systems Work
A carbine-length gas system places the gas port closer to the chamber than mid-length or rifle systems. This positioning delivers higher gas pressure and faster bolt unlock, which is why carbine gas is standard on shorter barrels.
The gas tube is a passive stainless steel conduit. It channels expanding gas from the barrel port back through the upper receiver to cycle the action. The roll pin secures the tube inside the gas block.
Installation and Compatibility
Installation requires removing the handguard, aligning the tube through the gas block, and driving the roll pin to lock it in place. The gas tube then extends through the upper receiver and seats into the gas key atop the bolt carrier.
Carbine gas tubes work only with carbine-length gas blocks. If you are uncertain which gas system length your barrel uses, call 817-393-4000 to confirm before ordering. Mixing tube lengths and gas port positions will prevent reliable cycling.
When to Replace a Gas Tube
Gas tubes fail from carbon fouling, heat erosion at the gas port end, or physical damage during disassembly. Symptoms include short-stroking, failure to eject, or visible cracks and pitting.
Replacement is straightforward. Drift out the old roll pin, remove the tube, clean the gas block port, and install the new tube. Many builders keep a spare on hand because a damaged gas tube stops the rifle cold.
Western Sport is a licensed FFL/SOT dealer and gunsmith shop serving North Texas and the DFW area since 2007. Owner and gunsmith Lance Rankin provides on-site builds, repairs, and expert advice. Call 817-393-4000 with questions about gas system components or AR-15 assembly.
Frequently Asked Questions
What is the difference between carbine, mid-length, and rifle gas tubes?
The three gas tube lengths correspond to different gas port positions on the barrel. Carbine tubes are the shortest and pair with gas ports closest to the chamber. Mid-length tubes are longer and used on barrels with ports farther forward. Rifle-length tubes are the longest. Using the wrong length will prevent the gas tube from reaching both the gas block and the bolt carrier gas key.
Will this carbine gas tube fit my 16-inch AR-15 barrel?
Most 16-inch AR-15 barrels use carbine-length gas systems, but some are drilled for mid-length. Check your barrel specifications or measure the distance from the chamber face to the gas port. If you are unsure, call 817-393-4000 and we will help you identify the correct gas tube length for your barrel.
How do I install the roll pin that secures the gas tube?
Insert the gas tube through the gas block so the tube end sits flush or slightly recessed. Align the roll pin hole in the tube with the hole in the gas block. Use a roll pin punch and hammer to drive the pin through until it is centered and flush on both sides. Work on a padded surface to avoid marring the gas block finish.
Can a bent or damaged gas tube cause cycling problems?
Yes. A bent gas tube may not align properly with the gas key on the bolt carrier, reducing gas flow and causing short-stroking or failure to cycle. Carbon buildup inside the tube or erosion at the gas port end can also restrict flow. Inspect the tube during cleaning and replace it if you see visible damage or persistent cycling issues.
Do I need to replace the roll pin every time I remove the gas tube?
Roll pins can usually be reused once or twice if removed carefully and not deformed during extraction. However, they are inexpensive and a fresh pin ensures a tight fit. Many armorers replace the pin whenever they remove the gas tube to avoid the risk of a loose connection.
Does Western Sport offer gunsmithing services for AR-15 upper assembly?
Yes. Western Sport provides full gunsmithing services at our Roanoke, Texas location, including AR-15 upper assembly, barrel installation, gas system setup, and troubleshooting. Call 817-393-4000 to discuss your build or bring your parts in for professional installation.
Additional information
Weight
0.25 lbs
Reviews
There are no reviews yet.
Be the first to review “Carbine Length Gas Tube w/ Pin” Cancel reply
Reviews
There are no reviews yet.