Components of the AR Firing Pin Assembly
The Firing Pin
The heart of the assembly, the firing pin, is a slender, hardened steel rod. This crucial piece is responsible for making direct contact with the primer, igniting the propellant within the cartridge. The firing pin must be robust enough to withstand the force of the hammer without bending or breaking. The tip is precision-machined to ensure consistent primer strikes. The quality of the steel and the manufacturing process are important factors determining the firing pin’s durability and longevity. A well-made firing pin will endure thousands of rounds before showing signs of wear.
The Firing Pin Retaining Pin
The firing pin retaining pin, also known as a cotter pin, plays a crucial role in securing the firing pin within the bolt carrier group. This small, usually wire-shaped piece is inserted through a hole in the bolt carrier and holds the firing pin in place. The retaining pin prevents the firing pin from inadvertently moving forward and potentially causing a premature discharge. Correct installation and maintenance of the retaining pin are essential for the safe operation of the AR. Damage to the retaining pin can impede the function of the firing pin, leading to malfunctions.
The Bolt Carrier Group (BCG) Considerations
The bolt carrier group (BCG) provides the housing for the firing pin assembly, and the BCG is the workhorse of the AR platform. It is in the bolt carrier that the firing pin travels back and forth. The BCG houses the firing pin, firing pin spring, and often other related components. The BCG’s design ensures that the firing pin is properly aligned with the primer and has enough clearance to move freely, delivering an accurate strike every time. The bolt carrier group also facilitates the cycling of the action by extracting spent casings, feeding new rounds, and finally, seating the new round and chambering it, all of this is made possible by the successful function of the firing pin and the proper ignition of the cartridge.
Function of the AR Firing Pin Assembly
The AR firing pin assembly functions through a carefully orchestrated sequence of events. When the trigger is pulled and the hammer is released, the hammer strikes the firing pin. The hammer’s impact drives the firing pin forward with significant force. The firing pin then strikes the primer of the chambered cartridge. The primer is designed to be sensitive to impact. When the firing pin makes contact, it crushes the primer material, initiating a small explosion. This initial explosion then ignites the propellant within the cartridge. As the propellant burns rapidly, it generates expanding gases, which propel the bullet down the barrel. The entire process, from trigger pull to the bullet exiting the muzzle, happens in a fraction of a second, and the firing pin is a critical element in the initial stage of this crucial event.
The reliable function of the AR firing pin assembly is integral to both the accuracy and the reliable cycling of the rifle. If the firing pin fails to ignite the primer, the rifle will experience a failure to fire. A weak firing pin strike can also contribute to this issue. Consistent and forceful primer strikes are vital to ensure that the propellant ignites every time. A malfunction within the firing pin assembly can also affect the extraction of spent casings, creating another common issue. A clean, properly maintained firing pin assembly contributes directly to the AR’s overall reliability.
Maintenance and Cleaning
Proper maintenance of the AR firing pin assembly is crucial for ensuring its longevity and consistent function. Routine cleaning and inspection can help prevent malfunctions and identify potential problems before they become major issues.
Regular cleaning is a simple and essential part of AR ownership. Disassembling the bolt carrier group is often the first step for cleaning the firing pin. First, safely remove the bolt carrier from the upper receiver and then remove the firing pin retaining pin. The firing pin can then be removed from the bolt carrier group. After removing the firing pin, clean it thoroughly with a solvent specifically designed for firearms. A toothbrush or cleaning pick can be used to remove any carbon buildup. The bolt carrier group should also be cleaned and scrubbed of carbon buildup. Many quality cleaning products can assist with this.
The application of a small amount of gun oil is recommended, which should lubricate the firing pin and facilitate its smooth movement within the bolt carrier. A dry firing pin can stick and lead to malfunctions. Use a high-quality lubricant that is specifically formulated for firearms and apply it sparingly.
Inspect the firing pin for any signs of wear and tear. Look for any cracks, bends, or damage to the tip. Carefully examine the firing pin retaining pin for signs of bending, damage, or wear. Replace any damaged components immediately. It’s also essential to have some spares of these parts readily available.
Proper storage of the AR firing pin assembly is important when the rifle is not in use. Always store the AR, unloaded, in a safe, dry place. This can include storing the BCG separately from the receiver and upper. Protect the firing pin from extreme temperatures, moisture, and corrosive substances.
Troubleshooting Common Issues
Even with regular maintenance, issues with the AR firing pin assembly can sometimes arise. Several common malfunctions are directly related to this component, and understanding these issues can aid in troubleshooting.
Failure to fire (FTF) is a common issue that can be related to the firing pin assembly. Possible causes of this issue include light primer strikes, where the firing pin does not hit the primer with enough force to cause ignition. This is also possible due to the firing pin itself having damage, or a broken tip. The improper installation of the firing pin retaining pin could also prevent the firing pin from functioning correctly. Troubleshooting such issues involves a multi-step process. First, inspect the firing pin for any damage and for obstructions, such as carbon build-up. Verify that the firing pin can move freely within the bolt carrier. Confirm that the primer itself is not faulty by chambering another round. If the problem persists, it may be necessary to replace the firing pin spring or the firing pin itself.
Failure to extract is a malfunction where the spent casing does not leave the chamber. If the firing pin strikes the primer but the round does not fire, the problem might not be with the firing pin itself. However, a weak firing pin spring can contribute to this problem. As the firing pin hits the primer, it needs to be able to get out of the way of the bolt. A damaged or fatigued firing pin spring may not return the firing pin to its initial position after the strike. This can cause the firing pin to interfere with the extraction process.
Sometimes, the firing pin can become stuck or bind within the bolt carrier. This can result from an accumulation of debris, such as carbon, or a lack of lubrication. To resolve this, disassemble the bolt carrier, clean the firing pin and its surrounding area meticulously, and re-lubricate the assembly.
Upgrades and Modifications
Several aftermarket options exist to enhance the AR firing pin assembly. Many manufacturers offer improved firing pins made from high-quality materials, often tool steel, or with enhanced coatings for increased durability and resistance to wear. The use of a stronger firing pin spring can ensure more forceful primer strikes, helping to improve ignition reliability, especially with hard primers.
Safety Considerations
Safety is paramount when working with firearms. Always handle the AR with extreme care, and always follow all safety rules. Safe firearm handling starts with the understanding of the basic safety rules. Always assume every firearm is loaded. Never point the muzzle at anything you are not willing to destroy. Keep your finger off the trigger until you are ready to shoot. And always be certain of your target and what is beyond it.
Always ensure that the rifle is unloaded and the chamber is clear before performing any maintenance on the firing pin assembly. Properly disassemble the bolt carrier group according to the manufacturer’s instructions. Use the correct tools for the job, and take your time to avoid damaging any components. When reassembling, make sure all parts are correctly installed, and the firing pin retaining pin is firmly in place.
Conclusion
The AR firing pin assembly is an important component that is essential for the proper functioning of an AR-15. Understanding the firing pin’s role, maintaining it properly, and knowing how to troubleshoot common problems is essential for every AR owner. Regular maintenance and inspection, along with a knowledge of the components and functions, will help you ensure your rifle functions flawlessly. By taking the time to understand this assembly and care for it, you can significantly contribute to the reliability and safe operation of your AR-15. Make regular inspection of the firing pin assembly part of your routine when you clean your rifle.
