Understanding the Disconnector Spring
What is the Disconnector?
The AR-15 is a marvel of engineering, a firearm platform built on the principle of modularity. This allows for easy customization and adaptation to different needs. The heart of this adaptability, and its reliability, lies in the individual components working in harmony, within the fire control group. The fire control group consists of numerous parts, each playing a vital role in the cycle of firing. At the core, the disconnector spring is a critical element in this cycle.
But what is the disconnector, and why is it so important? The disconnector is a small, often crescent-shaped piece of metal located within the lower receiver, nestled amongst the trigger, hammer, and sear. Its primary function is to prevent the firearm from firing multiple rounds with a single pull of the trigger – a scenario often referred to as “full auto” or “doubles” (or, worse, “triples”). It achieves this by intercepting the hammer and holding it back after the bolt cycles and chambers a new round, only allowing it to be released again when the trigger is released and pulled a second time.
The disconnector spring’s function is deceptively simple yet fundamentally important. The spring, typically a tightly wound coil of steel wire, provides the necessary upward pressure on the disconnector. This upward pressure is what allows the disconnector to engage the hammer. Without this spring, the disconnector would likely fail to catch the hammer, causing it to “follow the bolt” and result in uncontrolled, potentially dangerous firing sequences. The proper function of this spring ensures the precise control over the firing cycle that is critical to responsible firearm ownership.
The materials used in the manufacture of disconnector springs are important. While the spring itself is typically made of steel, the quality of the steel and the precision of its manufacturing is critical for longevity and reliability. The spring must be able to withstand repeated compression and expansion cycles without losing its spring rate. The spring needs to consistently return the disconnector to its correct position with each trigger reset. Poorly made springs may corrode quickly, lose their tension, or even break, leading to malfunctions.
Functioning of the Disconnector System
To truly appreciate the role of the disconnector spring, it’s helpful to trace the firing cycle, and understand the dynamics of the disconnector during each stage. Imagine that the firearm is loaded, the safety is off, and you’re ready to fire. Here’s a step-by-step breakdown:
You pull the trigger. This action pivots the trigger, releasing the sear, which in turn releases the hammer. The hammer is propelled forward by the force of the mainspring, striking the firing pin and igniting the primer of the cartridge.
The expanding gases from the ignited gunpowder propel the bullet down the barrel. Simultaneously, these gases force the bolt carrier group (BCG) backward, extracting the spent casing from the chamber.
As the bolt carrier group moves backward, the disconnector is held in place by the hammer. The BCG then engages the hammer’s hooks. During this movement the hammer is cocked back and resets by the bolt carrier.
The bolt carrier continues its rearward travel and then moves forward, stripping a fresh round from the magazine, chambering it, and locking the bolt.
As the bolt carrier group closes and returns to battery (fully forward), the hammer is held back by the disconnector, preventing it from falling forward and striking the firing pin again.
Now, here’s where the critical role of the disconnector spring becomes apparent. It’s the force of this spring that holds the disconnector in place against the hammer. Without this pressure, the disconnector might not catch the hammer properly, resulting in a malfunction.
The trigger is now released. As the trigger is released, the trigger bar and the disconnector are allowed to return to their normal position.
Only when the trigger is released and then pulled again is the hammer released by the disconnector, ready to strike the firing pin of the next round.
Signs of a Failing or Worn Disconnector Spring
A failing or worn disconnector spring can manifest in various ways, all of which compromise the safe and reliable operation of your AR-15. Being able to identify these signs early is essential. Here are some of the most common symptoms:
A potentially catastrophic malfunction is the occurrence of doubles or triples. This is when the firearm fires two or three rounds with a single pull of the trigger. This typically happens because the hammer is not properly being caught by the disconnector after the first shot and the bolt carrier is not correctly returning the hammer to it’s locked position.
Another serious indicator is “hammer follow”. Here, the hammer follows the bolt forward, striking the firing pin before the trigger is pulled. The hammer is not fully “reset”. This can happen if the spring lacks sufficient pressure, fails completely, or is damaged.
Misfires, or failures to fire, can also indicate a disconnector spring issue. The hammer might not be fully cocked or may not strike the firing pin with sufficient force. A weak disconnector spring can contribute to these problems.
Increased trigger pull weight or a less responsive trigger feel can also signal a problem. The added friction or improper seating of components can make the trigger feel sluggish or heavy.
When troubleshooting, it’s helpful to perform a basic inspection and some simple tests. Check the disconnector spring for obvious signs of wear, such as compression, distortion, or corrosion. A visual inspection of the spring itself will often reveal obvious problems. You should also inspect the disconnector and other fire control components for damage. If the spring shows any signs of malfunction, it’s essential to replace it.
Replacing the Disconnector Spring
If you’ve identified a problem with your disconnector spring, replacement is usually a straightforward process. However, it’s crucial to approach this task with care and the utmost regard for safety.
Before beginning any work on your AR-15, always ensure that the firearm is unloaded and the chamber is clear. Double-check that the magazine is removed and that no ammunition is present. Point the muzzle in a safe direction during all work. Wear safety glasses. A secure workbench and good lighting are helpful for easy inspection.
You’ll need a few tools and materials. The main item is, of course, the replacement disconnector spring. Additional tools you’ll need are a punch and a hammer. Gunsmithing tools like slave pins can be helpful in the disassembly and reassembly process.
Here’s a general step-by-step guide for replacing the disconnector spring:
First, remove the upper receiver from the lower receiver. Next, remove the pistol grip and the trigger. Be careful not to lose any small springs or pins during this disassembly process.
Next, you will need to remove the hammer and disconnector assembly from the lower receiver. Be careful to maintain the alignment of the parts.
Once the hammer assembly is free of the lower receiver, it’s time to separate the components. The hammer will now need to be disassembled to allow the disconnector spring to be removed. This can be accomplished by removing the hammer pin.
Once you’ve done this, it’s now time to insert the replacement spring. You will reinstall the disconnector and hammer using the hammer pin. Make sure the spring is properly seated in its designated place and that it has a good amount of tension.
Reassemble all the components back into your lower receiver. Ensure all pins are properly seated and secured. Double-check that the trigger and hammer assembly operates smoothly and as intended.
After reassembling the lower receiver, you should perform a function test before putting the firearm back into operation. Make sure to function-test the weapon in a safe, clear area.
Choosing a Replacement Spring
When selecting a replacement disconnector spring, choosing a quality product is essential for safety and reliability. Many manufacturers offer AR-15 parts. However, not all springs are created equal.
Look for springs manufactured by reputable brands known for their quality control and adherence to industry standards. Choose springs made from high-quality materials, specifically designed for the AR-15 platform.
Consider what your intended use of the firearm is when deciding to upgrade any parts. A spring designed for general use may not be appropriate for a specific type of trigger.
Maintenance and Preventative Measures
Regular maintenance is key to preserving the lifespan and reliability of your AR-15, including the disconnector spring. Make it a habit to visually inspect the disconnector spring and other fire control components every time you clean your firearm.
A small amount of a quality lubricant, such as a gun-specific oil, can help to ensure that the fire control group operates smoothly. However, avoid over-lubrication, as this can attract dirt and debris, which can lead to malfunctions.
During disassembly and reassembly, be careful not to damage the disconnector spring. Avoid bending or over-compressing the spring during installation.
By understanding the crucial role of the AR-15 disconnector spring, recognizing the signs of its failure, and knowing how to replace it, you can contribute to the safe, reliable operation of your firearm. Always prioritize safety, and follow the proper procedures when working on your AR-15.
It is recommended that you have a qualified gunsmith inspect the firearm if you have questions or any doubts during this process. This ensures the firearm functions correctly and safely.
