Understanding the Core of the AR-15 Trigger Mechanism
Before we can dissect the “trigger not resetting” issue, it’s crucial to grasp the fundamental workings of the AR-15’s trigger system. This system is more than just the part you pull; it’s a carefully engineered dance of components designed to release the hammer, initiating the firing sequence.
The key players in this mechanical ballet are:
- The Trigger: The component the shooter interacts with to initiate the firing cycle.
- The Hammer: A pivoting component that strikes the firing pin, igniting the cartridge.
- The Sear: This crucial part holds the hammer in a cocked position until the trigger is pulled.
- The Disconnector: A safety mechanism that prevents the hammer from dropping if the trigger is released before the bolt carrier group (BCG) has fully returned to battery. This component also plays a role in single-shot function.
- Springs: The trigger spring, hammer spring, and disconnector spring. These are essential for returning the trigger to its forward position, powering the hammer’s strike, and ensuring proper disconnector function.
- Pins: These small but vital components secure the trigger, hammer, and disconnector within the lower receiver.
The process is relatively straightforward:
- When you pull the trigger, it moves, engaging the sear.
- The sear releases the hammer.
- The hammer, driven by its spring, strikes the firing pin.
- The firing pin ignites the primer, which causes the powder to burn and propel the bullet.
- As the bolt carrier group (BCG) cycles back, the disconnector moves, allowing the trigger to reset.
- The trigger, once released, can now catch the hammer again.
Any disruption in this carefully synchronized sequence can lead to the trigger not resetting problem.
Unraveling the Usual Culprits: Why Your Trigger Stays Put
Now, let’s explore the common factors that cause an AR-15 trigger not resetting. Identifying the root cause is the first step in finding a solution.
Dirty or Neglected Trigger Components
Over time, the trigger assembly can accumulate a build-up of carbon residue from spent cartridges, unburnt powder, and other debris. This accumulation acts as a lubricant killer, preventing smooth movement between the parts. Debris can find its way into the critical interfaces between the trigger, hammer, sear, and disconnector. The result? Friction, binding, and a trigger that stubbornly refuses to reset. Regular cleaning is essential.
Incorrectly Installed or Damaged Parts
Improper assembly is a significant contributor to trigger problems. If the trigger, hammer, or disconnector are installed incorrectly, they may not function properly. A misaligned sear could fail to catch the hammer or create too much friction. Likewise, if the trigger or other components are damaged from wear, improper usage, or abuse, this may cause your AR-15 trigger not resetting.
It’s also critical to note the quality of the parts. Some aftermarket triggers may not be compatible with the standard specs.
Spring Issues and Their Implications
The springs within the trigger assembly are integral to its functionality. If a trigger or disconnector spring is weak, broken, or improperly seated, the affected component might not operate correctly. This might lead to a trigger that doesn’t reset or an inconsistent trigger pull. A weak hammer spring can lead to light primer strikes or a failure to ignite the cartridge.
Bolt Carrier Group (BCG) Interaction
The AR-15’s action relies on the smooth rearward movement of the bolt carrier group (BCG) to reset the trigger. If the BCG doesn’t travel far enough back during the cycling process, this can lead to issues. Similarly, there may be a problem if the hammer drags on the BCG. A gas system malfunction or a weak buffer spring could prevent the BCG from cycling fully, preventing the trigger from resetting.
Ammunition Related Problems
The ammunition used in your AR-15 can sometimes be the culprit. If you’re using underpowered rounds that do not produce enough recoil to reliably cycle the action, the trigger may not reset. Defective primers, which fail to ignite the powder properly, can also lead to malfunctions.
Buffer and Spring Inconsistencies
The buffer and buffer spring play a crucial role in the AR-15’s cycling. If the buffer is too heavy or the buffer spring is too stiff for the ammunition being used, or the gas system, the bolt carrier may not cycle far enough back to allow the trigger to reset. A damaged or incorrect buffer or spring can also create problems.
Over-Tightened or Incorrectly Installed Pins
The pins that secure the trigger, hammer, and disconnector must be installed correctly and at the proper depth. If they’re over-tightened, they can bind the components, causing friction and preventing them from moving freely, leading to a trigger that won’t reset.
Troubleshooting Steps: Bringing Your Trigger Back to Life
When your AR-15 trigger not resetting, it’s time for some systematic troubleshooting.
Safety First Always
Before you begin any work on your firearm, always follow these essential safety protocols:
- Clear the Firearm: Remove the magazine, lock the bolt back, and visually and physically inspect the chamber to ensure it’s empty.
- Confirm Unloaded: Re-emphasize that the rifle is unloaded.
- Safety Glasses: Wear appropriate eye protection throughout the troubleshooting process.
- Work Environment: Choose a well-lit, clean, and organized workspace.
Visual Examination: The First Line of Defense
Disassembly of the lower receiver is usually the first step. Here’s how:
- Remove the Upper Receiver: Separate the upper receiver from the lower receiver by removing the takedown and pivot pins.
- Remove the Buffer and Buffer Spring: Remove the buffer and buffer spring to help with accessibility.
- Remove the Trigger, Hammer, and Disconnector: Use a punch and a small hammer to carefully remove the trigger, hammer, and disconnector pins. Take note of which way they come out so you can replace them properly.
- Inspect Components: Examine the trigger, hammer, sear, and disconnector for signs of damage or excessive wear. Look for burrs, chips, or unusual wear patterns on the engagement surfaces. Check the trigger and disconnector springs for proper seating and signs of wear or breakage.
Cleaning: A Path to Smooth Operation
Proper cleaning is vital to restoring smooth trigger function.
- Solvent Selection: Use a high-quality gun cleaning solvent designed to remove carbon and debris.
- Application: Apply the solvent liberally to the trigger, hammer, sear, and disconnector.
- Brush & Wipe: Use a nylon brush and cotton swabs to scrub away carbon buildup and gunk from the components. Pay close attention to the engagement surfaces and pivot points.
- Lubrication: After cleaning, lightly lubricate the components with a gun oil or a dedicated trigger lubricant. Avoid over-lubricating, which can attract more dirt and debris.
Testing and Manual Evaluation
Reassemble the lower receiver components after cleaning and inspection.
- Dry-Fire Test: Carefully dry-fire the rifle, observing the movement of the trigger, hammer, and sear. Check to see if the trigger resets.
- Manual Cycling: Manually cycle the action by pulling the charging handle. Observe the BCG’s movement and make sure it fully cycles.
- Function Test: Test with different ammunitions.
Replacing Problematic Parts
If you identify a damaged or worn component during your inspection, replacing it is often the best course of action. Purchase replacement parts from a reputable supplier.
Solutions and Preventive Maintenance
Preventing future trigger malfunctions is far easier than fixing them.
Consistent Cleaning and Routine Maintenance
Make trigger cleaning a regular part of your shooting routine. After each range session, disassemble the lower receiver and clean the trigger assembly. This will prevent the buildup of carbon and debris that can lead to malfunctions.
Component Upgrades: Enhanced Performance
Consider upgrading your trigger to a high-quality aftermarket system. These systems often offer smoother trigger pulls, crisper breaks, and improved reliability. Research different options and choose a trigger that suits your shooting needs.
Ammunition Selection: Choose Wisely
Use quality ammunition that is appropriate for your AR-15. This ensures reliable cycling and minimizes the risk of malfunctions.
Buffer and Spring Compatibility
Make sure the buffer and spring are the correct weight for your AR-15 configuration and ammunition.
Professional Gunsmithing Assistance
If you’re not comfortable with the troubleshooting process or the malfunction persists, seek help from a qualified gunsmith.
Conclusion
When your AR-15 trigger not resetting, it can be frustrating and potentially unsafe. By understanding the underlying mechanics, common causes, and troubleshooting steps, you can effectively diagnose and resolve this issue. Proper maintenance, diligent cleaning, and a keen eye for detail are your best allies in preventing future malfunctions. By applying the information in this guide, you’ll be well on your way to restoring your AR-15 to its reliable, accurate, and enjoyable performance.
Always prioritize gun safety and seek professional help when needed.
