Understanding the AR-15’s Cycle
Gas System
The AR-15’s power comes from a gas system. When you fire a round, a portion of the high-pressure gas generated by the explosion is channeled from the barrel through a small hole called the gas port. This gas travels through a gas block, which directs the gas, and then continues its path through a gas tube. The gas tube carries the gas back to the bolt carrier group, the engine of the rifle’s operation. The gas pushes the bolt carrier group rearward, initiating the cycling process.
The Cycle of Operation
The actual cycle of operation is a series of steps:
As the rifle fires a round, the high-pressure gas moves down the barrel and exits through the gas port. The gas flows into the gas block and through the gas tube into the bolt carrier group. The expanding gas forces the bolt carrier group backward, cycling the action.
- Feeding: This begins as the bolt carrier group moves rearward, stripping a fresh round from the magazine. The bolt face then guides the bullet into the chamber, positioning it for firing.
- Firing: The firing pin strikes the primer of the cartridge, igniting the propellant. This combustion generates the force needed to propel the bullet down the barrel.
- Extracting: After the bullet exits the barrel, the spent casing remains in the chamber. The bolt carrier group continues rearward, its extractor, a small hook-shaped component on the bolt, firmly grips the rim of the spent casing, pulling it from the chamber.
- Ejecting: As the bolt carrier group continues its rearward journey, the spent casing is directed towards the ejection port and ejected from the rifle.
Once the bolt carrier group reaches the end of its rearward travel, it is pushed forward by the buffer and spring. The cycle then begins again with feeding.
Common Reasons an AR-15 Fails to Cycle
A failure to cycle can arise from a multitude of factors, each impacting the delicate balance of the AR-15’s operation. Understanding these common issues is crucial for accurate diagnosis.
Gas System Issues
The gas system, as mentioned, is the lifeblood of the AR-15’s cycling. If the gas system is not functioning correctly, the rifle will not cycle reliably.
Insufficient Gas
This is often a primary culprit. The bolt carrier group simply isn’t receiving enough energy to complete the cycling process.
Gas Leaks
Check for leaks in the gas block, gas tube, or around the gas key. A leak means less gas is reaching the bolt carrier group. The gas block might not be properly sealed to the barrel or the gas tube could be damaged.
Gas Port Obstruction
Carbon buildup, dirt, or debris within the gas port can restrict gas flow. Check the barrel to make sure the gas port is unobstructed.
Undersized Gas Port
The gas port may be too small for the ammunition you’re using or the environmental conditions, particularly if shooting in cold weather. This means insufficient gas is reaching the bolt carrier group.
Excessive Gas
While less common, too much gas can also cause problems. The bolt carrier group may cycle too violently, leading to malfunctions or premature wear and tear.
Overgassing
Can lead to extraction and ejection problems. Consider adjusting the gas block (if adjustable), or changing buffer or spring weights.
Gas System Misalignment
If the gas tube is bent, misaligned, or not properly seated in the gas key on the bolt carrier group, the gas will not be properly channeled, leading to malfunctions.
Bolt Carrier Group Problems
The bolt carrier group (BCG) is the driving force behind the cycling process. Problems within this assembly can quickly lead to malfunctions.
Carrier Sticking
If the bolt carrier group doesn’t slide freely within the receiver, the cycling process will be disrupted. This can be caused by dirt, carbon buildup, lack of lubrication, or, less frequently, damage to the carrier.
Carrier not freely sliding in the receiver due to dirt, carbon buildup, or damage.
Dry firing without lubrication can cause this to occur.
Bolt Issues
Problems with the bolt itself can also halt cycling.
Extractor Issues
The extractor, which pulls the spent casing from the chamber, can fail. A worn extractor, a weak extractor spring, or damage to the extractor hook will cause extraction failures.
Ejector Problems
A stuck or broken ejector can prevent proper ejection.
Bolt Not Fully Closing
The bolt may not fully close, potentially due to a tight chamber, insufficient lubrication, or a problem with the bolt carrier group.
Ammunition’s Role
The ammunition you use plays a crucial role in the AR-15’s cycling. Using the wrong type of ammunition can cause malfunctions.
Underpowered Ammunition
Ammunition that does not generate sufficient gas pressure to cycle the rifle will result in failures to cycle.
Overpressure Ammunition
Conversely, ammunition that generates excessive pressure may create malfunctions, excessive wear, and potentially damage the rifle.
Bad Ammo
Defective cartridges with faulty primers, or other issues can prevent proper cycling.
Buffer System Challenges
The buffer system, which includes the buffer and buffer spring, is responsible for absorbing the energy of the bolt carrier group and returning it forward.
Incorrect Buffer Weight
The buffer weight must be balanced for the specific configuration of your rifle. If the buffer is too heavy, the rifle may not cycle reliably. If it is too light, it may cycle too fast and potentially cause damage or failure to extract the case.
Buffer Spring Problems
A worn, damaged, or incorrect buffer spring can also lead to cycling problems.
Magazine Matters
The magazine feeds rounds into the rifle. If your magazine is not working correctly, the rifle will not cycle.
Defective Magazines
Damaged, dirty, or poorly designed magazines can cause feeding failures.
Additional Considerations
Several other factors can contribute to cycling failures:
- Tight Chamber: A tight chamber, which can occur in some barrels, may prevent the spent casing from extracting, causing the rifle to malfunction.
- Insufficient Lubrication: A lack of lubrication on moving parts, particularly the bolt carrier group, can impede the cycling process, leading to malfunctions.
- Dirty Firearm: Carbon buildup and debris, especially in the chamber and gas system, can cause malfunctions.
- Out-of-Spec Parts: Mixing components that are not compatible or out of specification can cause cycling problems.
- Operator Error: Improper assembly or handling can also lead to issues.
Troubleshooting Your Rifle
Once you suspect a malfunction, a systematic approach to troubleshooting is vital.
Starting with the Basics
Begin by making sure the firearm is unloaded and the safety is engaged. Visual inspection of the magazine and ammunition should be performed.
Detailed Steps to Diagnose
- Gas System Investigation:
- Carefully inspect the gas block and gas tube for gas leaks.
- Clean the gas port.
- Make sure the gas tube is clear of damage.
- Bolt Carrier Group Examination:
- Disassemble and thoroughly clean the bolt carrier group.
- Check the extractor’s condition, and make sure the spring is functioning correctly.
- Inspect the ejector to ensure it’s not damaged.
- Ammunition Review:
- Attempt firing with different ammunition types to see if the problem persists.
- Check for primer strikes.
- Buffer System Checkup:
- Verify the buffer weight matches your setup.
- Confirm the buffer spring’s condition.
- Magazine Evaluation:
- Test your rifle with known-good magazines.
- Chamber Inspection:
- Try loading and extracting a round by hand to see if the chamber allows easy entry and extraction.
Simple Solutions
In many cases, simple solutions can resolve cycling issues.
- Proper Lubrication: Applying lubricant to the moving parts of the BCG, charging handle, and bolt, can significantly help.
- Parts Replacement: Worn or damaged parts can be easily replaced.
- Thorough Cleaning: A good cleaning may resolve some of the issues.
Correcting Cycling Malfunctions
When diagnosing malfunctions, finding the correct solution to resolve the issue is essential.
Gas System Solutions
- Secure the gas block.
- Replace the gas tube if necessary.
- Have a professional gunsmith drill or ream out the gas port.
- Install an adjustable gas block.
Bolt Carrier Group Corrections
- Change the extractor, spring, or ejector.
- Clean and lubricate the BCG.
Buffer System Adjustments
- Use the right buffer weight and spring.
Ammunition Change
- Try another brand or type of ammo.
Other solutions
- Clean and lubricate the firearm.
- Replacing magazines.
- Replace the barrel if the chamber is the problem.
- Professional Gunsmith if needed.
Maintenance and Prevention
Regular care and preventative maintenance are the keys to ensuring reliable operation of your AR-15.
Regular Cleaning
Clean your rifle frequently. The chamber, bolt carrier group, gas system, and magazine are areas that require extra attention.
Proper Lubrication
Use the correct lubricant for your rifle.
Frequent Inspection
Check for wear and tear. Identifying potential problems early prevents more serious issues.
Quality Parts
Use high-quality, compatible components when replacing or upgrading parts.
The AR-15, a truly versatile firearm, requires that the operator has knowledge and skills to maintain its functioning.
If your AR-15 won’t cycle, your safety may be impacted. If you are unsure of how to resolve a problem, seek professional guidance. With proper care, maintenance, and troubleshooting, your AR-15 will reliably serve its purpose for years to come. Take the time to understand your rifle, and it will reward you with dependable performance.
