Understanding the AR-15 Gas System
The Gas Tube’s Role
The AR-15 platform is a marvel of modern firearms engineering, renowned for its modularity, accuracy, and adaptability. This versatility, however, also means that maintaining the AR-15 is a crucial aspect of its ownership. Just like any precision instrument, the AR-15 requires regular care and attention to ensure optimal performance and longevity. One of the most vital components requiring meticulous upkeep is the AR-15 gas tube. This often-overlooked part plays a critical role in the rifle’s reliable operation, and understanding how to properly clean it is essential for any AR-15 owner. This comprehensive guide will delve into the intricacies of the gas tube, explaining its function and providing a detailed, step-by-step process for cleaning it effectively.
How It Works
Before diving into the cleaning process, it’s crucial to grasp the gas system’s underlying principles. The AR-15 operates on a direct impingement system, which means that the gases produced by the ignited propellant are channeled directly into the bolt carrier group to cycle the action. At the heart of this system is the gas tube, a slender piece of metal that acts as a conduit for these high-pressure gases.
Function of the Gas Tube
The gas tube’s primary function is to direct a controlled amount of hot gas from the barrel, specifically from the gas port, back towards the bolt carrier group. The gas port, located on the barrel, is strategically positioned to tap into the expanding gases of the fired round. The gases travel through the gas block, which secures the gas tube, and subsequently through the gas tube itself. The gas tube extends to the upper receiver and connects to the gas key on the bolt carrier group.
When a round is fired, the gases from the explosion travel through the barrel and, upon reaching the gas port, are channeled into the gas tube. This high-pressure gas then flows through the gas tube and enters the gas key, driving the bolt carrier group rearward. This rearward movement unlocks the bolt, extracts the spent casing, and eventually compresses the buffer spring. The compressed buffer spring then pushes the bolt carrier group forward, chambering a fresh round and locking the bolt, readying the firearm for the next shot.
Consequences of a Dirty Gas Tube
A dirty or obstructed gas tube can severely impact the AR-15’s functionality. Carbon buildup, a byproduct of combustion, is the primary culprit. Over time, this carbon can accumulate within the gas tube, restricting gas flow and leading to various malfunctions. These issues can include failure to cycle, failure to eject spent casings, and inconsistent bolt carrier velocity. A clogged gas tube can also affect the rifle’s accuracy, as the inconsistent cycling can disrupt the rifle’s performance and accuracy. Regularly cleaning the gas tube is paramount to preventing these problems and ensuring the AR-15 operates flawlessly.
Signs of a compromised gas tube can be subtle, but often manifest during firing. If the rifle begins to experience failures to feed, or the bolt does not fully cycle, it’s an indication that the gas system may be malfunctioning. Additionally, a loss of accuracy and erratic ejection patterns can also point towards gas system problems.
Preparing for the Task: Essential Tools and Materials
Before you begin the cleaning process, ensure you have all the necessary tools and materials at hand. This will streamline the process and make it more efficient. Here’s a comprehensive list:
Required Items
- AR-15 Cleaning Kit (or Specific Components): A good quality cleaning kit is the foundation of any firearms maintenance routine. Ensure it includes the essentials like a cleaning rod, bore brushes, and various cleaning patches.
- Cleaning Rod: Select a multi-piece cleaning rod specifically designed for rifles of the AR-15’s caliber.
- Gas Tube Scraper: This is a highly recommended tool that simplifies the removal of carbon buildup from the interior and exterior of the gas tube.
- Cotton Swabs: Cotton swabs are invaluable for cleaning hard-to-reach areas, like the gas key.
- Gun Cleaning Solvent/Lubricant: Choose a high-quality gun cleaning solvent designed to dissolve carbon residue, followed by a lubricant to protect against corrosion and ensure smooth cycling.
- Pipe Cleaners: These are excellent for cleaning the gas tube interior and can reach into the tight spaces.
- Pliers or Multi-tool: You will need a suitable tool for removing and installing the gas tube roll pin. A specialized roll pin punch set can also be used.
- Eye Protection and Gloves: Safety should always come first. Protective eyewear will shield your eyes from debris, and gloves will keep your hands clean and protect them from solvents.
- Cleaning Mat (Optional, but Recommended): A cleaning mat provides a clean and organized workspace, protecting your rifle and your work surface.
Step-by-Step Cleaning: A Detailed Guide
Now that you have all the necessary tools and materials, let’s move on to the cleaning procedure.
Prioritizing Safety
Before any disassembly or cleaning, prioritize safety. Ensure the firearm is completely unloaded. Physically and visually inspect the chamber and magazine well to confirm that no ammunition is present. Point the muzzle in a safe direction throughout the entire process. Always wear eye protection and gloves to safeguard yourself from solvents and any potential debris. Work in a well-ventilated area to avoid inhaling fumes from the cleaning solvents.
Disassembly for Gas Tube Access
- Separate the Upper and Lower Receivers: Begin by separating the upper receiver from the lower receiver. Push out the takedown pin and the pivot pin to allow for separation.
- Remove the Handguard (If Applicable): If your AR-15 has a handguard, you may need to remove it to access the gas block and, subsequently, the gas tube. The method for removing the handguard will vary depending on the handguard type (e.g., free-float, drop-in). Follow the manufacturer’s instructions for your handguard.
- Locate and Remove the Gas Tube Roll Pin: The gas tube is secured to the gas block by a small roll pin. Using a roll pin punch (a roll pin starter punch is recommended) and a hammer, carefully tap the roll pin out of the gas block. Support the gas block with a stable surface. Be cautious not to bend or damage the roll pin.
- Extract the Gas Tube: Once the roll pin is removed, the gas tube can be gently pulled out from the gas block and the upper receiver. If the gas tube is stubborn, try gently wiggling it while pulling.
Cleaning the Gas Tube: Methods
The gas tube cleaning process can be approached using a few different methods.
Method: Cleaning Rod and Solvent
This is a common and effective method:
- Apply Solvent: Place a few drops of gun cleaning solvent onto a cleaning patch. Attach the patch to the cleaning rod.
- Insertion and Scrubbing: Carefully insert the cleaning rod with the solvent-soaked patch into the gas tube from the upper receiver side. Rotate the rod to scrub the internal surfaces of the gas tube.
- Repeat and Dry: Remove the patch and repeat the process with a clean patch, adding more solvent as needed until the patch comes out relatively clean. Finish by running a dry patch through the tube to remove any residual solvent or loosened carbon.
Method: Using a Gas Tube Scraper (Highly Recommended)
A gas tube scraper is a purpose-built tool, and will greatly help the cleaning effort:
- Scrape the exterior: If your scraper has an exterior cleaning feature, gently insert it over the gas tube’s exterior and scrape to remove any carbon buildup.
- Scrape the Interior: Insert the scraper into the gas tube’s interior. Rotate and maneuver the scraper to remove any stubborn carbon deposits.
- Inspection: After scraping, inspect the gas tube to ensure you’ve removed as much carbon as possible. You can use a light source to look through the tube to see if any buildup is remaining.
Method: Pipe Cleaners and Solvents
This method can be excellent to reach deep inside the gas tube:
- Solvent and Pipe Cleaner: Soak a pipe cleaner in the gun cleaning solvent.
- Insert and Scrub: Insert the pipe cleaner into the gas tube, gently rotating and working it back and forth to remove any carbon.
- Multiple Cleaners: Use several pipe cleaners, re-soaking them with solvent as needed.
- Remove Residue: Finish by using dry pipe cleaners to ensure all solvent and carbon particles are removed.
Cleaning the Gas Key
Don’t neglect the gas key. Carbon buildup within the gas key can also impair the firearm’s function.
- Solvent Application: Apply gun cleaning solvent to a cotton swab.
- Swab and Scrub: Use the cotton swab to clean the inside of the gas key, paying close attention to remove all carbon.
- Repeat as Necessary: Continue the process until the gas key is clean and free of any buildup.
Final Inspection and Lubrication
Once you’ve cleaned the gas tube and the gas key, give the components a final inspection.
- Visual Check: Visually inspect the gas tube for any signs of damage, such as dents or kinks, that might restrict gas flow. If the gas tube is damaged, replace it.
- Light Lubrication: Apply a small amount of gun oil or a dedicated firearms lubricant to a clean patch. Lightly lubricate the inside of the gas tube and the gas key. The lubricant will help protect the components from corrosion and ensure smooth operation.
Reassembly: Putting It Back Together
The reassembly process involves retracing the steps of disassembly.
- Reinstall the Gas Tube: Carefully insert the gas tube back into the gas block and the upper receiver. Ensure the gas tube is correctly aligned.
- Secure the Roll Pin: Align the gas tube and gas block and insert the roll pin. Using a roll pin punch and a hammer, carefully tap the roll pin until it is flush with the gas block.
- Reattach the Handguard: If you removed the handguard, reinstall it according to the manufacturer’s instructions.
- Reassemble Upper and Lower: Rejoin the upper and lower receiver by inserting the pivot and takedown pins.
Troubleshooting Common Issues
Even with regular cleaning, AR-15 rifles can sometimes experience problems. Here are some common issues related to a dirty gas tube, and other potential causes:
Common Issues
- Failure to Cycle: A dirty or obstructed gas tube is a frequent cause. The gas tube may not be allowing enough gas to push the bolt carrier group rearward. Other causes include: incorrect gas port size, weak or worn buffer spring, or improper ammunition.
- Failure to Eject: If the spent casing is not being ejected, it could be a sign of low gas pressure. A clogged gas tube, an improperly sized gas port, or a worn extractor can cause this.
- Short Stroking: This occurs when the bolt carrier group fails to cycle fully, meaning the bolt doesn’t go all the way back. This can be caused by an undergassed system, due to a restricted gas tube, or an overly heavy buffer and spring combination.
Regular Maintenance and Cleaning Frequency
The frequency with which you clean the gas tube depends on how frequently you use your AR-15 and the type of ammunition you’re using.
Cleaning Frequency
- After Every Range Session: If you shoot frequently, it’s advisable to clean the gas tube after every range session. This will minimize carbon buildup and ensure reliable operation.
- Periodic Inspections: Even if you don’t fire your AR-15 very often, perform periodic inspections of the gas tube and the entire gas system.
- High-Round Count: If you are shooting a significant number of rounds, consider cleaning it more frequently.
- Dirty Ammunition: Some ammunition may produce more carbon fouling than others. If you’re using ammunition known for being dirty, you may need to clean the gas tube more often.
Regular maintenance includes proper storage, inspection, and lubrication. When storing your AR-15, ensure it is in a secure, climate-controlled environment.
Conclusion
Cleaning the AR-15 gas tube is an essential part of owning and maintaining an AR-15. Regular cleaning will help prevent malfunctions, improve accuracy, and extend the life of your firearm. This guide has provided you with a clear and detailed understanding of the AR-15 gas tube and the step-by-step process for cleaning it. By following these instructions and making this process a regular part of your firearms maintenance routine, you can ensure that your AR-15 continues to perform reliably and safely for years to come. Proper cleaning not only keeps your AR-15 gas tube functioning at its best, but it helps keep your AR-15 operational. Remember to always prioritize safety and enjoy the process of keeping your firearm in top condition.
