Understanding the AR Pistol
Defining Features and Benefits
The AR platform has become a cornerstone of the firearms community, appreciated for its modularity, customization options, and widespread availability. One of the most interesting configurations within this family is the AR pistol, a compact and versatile firearm that has gained significant popularity. Building your own AR pistol can be a rewarding experience, giving you a deep understanding of the weapon and allowing for complete personalization. This comprehensive guide provides a detailed walkthrough, ensuring you’re well-informed about the entire process, from understanding the legal landscape to the final test fire. Let’s get started.
Key Terminology
An AR pistol, at its core, is a firearm built on the AR-15 platform but designed with specific features that differentiate it from a rifle. The defining characteristic is the absence of a shoulder stock, and instead, an arm brace or, in some cases, simply a pistol buffer tube. Additionally, the barrel length is typically kept under 16 inches. These features are crucial in complying with federal regulations, and the absence of a stock makes it legally classified as a pistol, not a rifle.
Benefits of Building an AR Pistol
The AR pistol offers some unique benefits. Their compact size makes them exceptionally maneuverable, ideal for close-quarters situations. The shorter barrel can also lead to a reduction in overall weight, improving portability. Furthermore, for some, building an AR pistol can be a cost-effective alternative to purchasing a complete rifle, particularly when you already own some compatible components. With the plethora of aftermarket parts, customization is endless, allowing owners to create a firearm that perfectly matches their needs and preferences.
Legal Requirements and Safety First
Federal and Local Regulations
Before acquiring any parts or starting your build, thoroughly research federal, state, and local laws regarding AR pistols. The regulations vary greatly depending on your location, and ignorance of the law is not a defense. In the United States, federal law, enforced by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), defines a pistol as a firearm designed to be fired by the hand and designed to have a grip or other feature which allows it to be fired from the hand. Certain states have additional restrictions on pistol features, barrel lengths, or magazine capacities, so it is absolutely essential to understand your local laws.
Importance of Safe Practices
Safety is paramount during the entire build process. Always treat every firearm as if it is loaded. Wear appropriate eye protection and work in a well-lit, uncluttered space. Familiarize yourself with the proper handling of tools and follow the manufacturer’s instructions when assembling parts. If you are not comfortable with any step of the process, do not hesitate to seek help from a qualified gunsmith or experienced builder. Ensure you’re knowledgeable about safe firearm handling, storage, and transportation practices.
Responsibilities of the Builder
It’s your responsibility to ensure that your AR pistol is built and used legally and responsibly. This includes ensuring your firearm does not violate any laws and that it is handled, stored, and transported safely. Always follow all applicable laws and regulations, and prioritize the safety of yourself and others.
Gathering the Necessary Components
Essential Components
Now comes the exciting part: acquiring the parts. Building an AR pistol requires a careful selection of components. The core components are:
- The Stripped Lower Receiver: This is the foundation of the pistol. Make sure you purchase a receiver designed to accept standard AR-15 components.
- The Stripped Upper Receiver: This completes the receiver set and houses the bolt carrier group and barrel.
- The Barrel: Crucial for determining accuracy and caliber. AR pistol barrels are generally under 16 inches in length. Carefully consider the caliber you want to build the pistol in (e.g., 5.56 NATO, .300 Blackout, 9mm).
- The Bolt Carrier Group (BCG): This includes the bolt, carrier, firing pin, and related components. It’s a critical piece of the puzzle, so ensure it’s compatible with your chosen caliber and barrel.
- The Charging Handle: Used to manually cycle the action and chamber a round.
- The Buffer Tube Assembly: Includes the buffer tube, buffer, and buffer spring. This manages the recoil of the firearm.
- Pistol Buffer Tube: This is specifically designed for AR pistols and often does not permit the attachment of a shoulder stock.
- Gas Block and Gas Tube: The gas block diverts gas from the barrel to cycle the action.
- Handguard: Provides a gripping surface and often houses accessories. It must be compatible with your barrel and gas system.
In addition to these essential parts, you will need a Lower Parts Kit (LPK). The LPK contains the various small parts required to complete the lower receiver. It generally includes the trigger, hammer, springs, pins, safety selector, magazine release, and bolt catch. Choosing quality components from reputable manufacturers is crucial for reliability and long-term performance.
Optional Components
Consider also purchasing optional components based on your preferences:
- Sights or Optics: Iron sights, red dot sights, or scopes can enhance accuracy.
- Muzzle Device: A flash hider, compensator, or suppressor (if legal in your area) can affect recoil and muzzle flash.
- Grips/Foregrips: Many users enjoy the option to add an additional grip to enhance the handling, but be sure to check your local laws as they often have restrictions.
- Ambidextrous Controls: Offer enhanced ergonomics for both right- and left-handed shooters.
Essential Tools for the Build
Core Tooling
Assembling an AR pistol requires a few specialized tools. Investing in quality tools will make the process easier and help prevent damage to your components. Essential tools include:
- AR-15 Armorer’s Wrench: Used for installing and removing the barrel nut, castle nut, and buffer tube.
- Torque Wrench: Essential for properly torquing the barrel nut and other components to the manufacturer’s specifications.
- Punch Set: Used for driving in and removing pins.
- Vice and Vice Blocks: Securely hold the upper and lower receivers during assembly.
- Gunsmithing Hammer: A quality hammer can be used to gently tap pins into place.
- Roll Pin Punch Set: A specialized punch set to assist in installing roll pins without damaging the components.
Optional Tools
While these are the essentials, some optional tools can further enhance the building experience:
- Upper Receiver Action Block: This block clamps into the upper receiver and allows you to use a vice to securely hold it during assembly.
- Mag Well block: This holds the lower receiver securely when working on the lower parts kit.
- Digital Torque Wrench: A more advanced torque wrench can provide more precise torque readings.
Putting It All Together: Step-by-Step Assembly
Lower Receiver Assembly
With the parts and tools in hand, it’s time to start building. The process is generally broken down into assembling the lower receiver and the upper receiver.
First, the lower receiver assembly. Place the lower receiver into a vise that uses a mag well block to prevent damage, but be sure to pad the vice jaws appropriately to prevent marring the finish. Install the trigger, hammer, and springs, carefully following the instructions provided with the LPK. Ensure the trigger and hammer move freely. Install the safety selector, followed by the bolt catch and magazine catch. Screw in your grip. Finally, install the buffer tube assembly, tightening the castle nut with the armorer’s wrench and appropriate torque. Ensure the buffer tube is properly aligned for your brace.
Upper Receiver Assembly
Next, let’s work on the upper receiver. Secure the upper receiver in a vice using upper receiver blocks. Install the barrel into the upper receiver and torque the barrel nut to the manufacturer’s recommended specifications. Pay close attention to the torque values to ensure the barrel is correctly installed. Install the gas block and gas tube. Slide the handguard over the barrel, aligning it properly, then secure it. Insert the bolt carrier group into the upper receiver. Slide the charging handle into place. Attach any muzzle device to the barrel, again, checking for proper torque.
Connecting Upper and Lower
Once both the upper and lower receivers are assembled, join them together. Insert the two receiver pins to connect them.
Function Check, Initial Test, and Adjustments
Functionality Testing
Once the AR pistol is assembled, a function check is necessary. Pull back the charging handle and ensure the bolt carrier group cycles smoothly and locks back on the bolt catch. Operate the safety selector to ensure it engages and disengages the trigger properly. Test the trigger pull to confirm it functions correctly.
Range Safety and First Shots
With the function check complete, you’re ready to take your creation to a safe firing range. Always perform a safety check before loading or firing the firearm. Load a single round and test fire the pistol. Observe the spent casing to ensure the ejection process is proper. Check the buffer, gas port, and gas block, and make sure everything is functioning properly.
Troubleshooting Malfunctions
If there are any malfunctions during the first test fire, such as failure to feed or eject, you may need to make adjustments. Check the gas system for leaks, ensure the magazine is properly seated, and verify that the buffer tube is correctly installed. If the pistol is short stroking, it may be necessary to adjust the gas block or replace the buffer and spring.
Maintenance, Cleaning, and Customization
Routine Cleaning
Regular maintenance is crucial to keeping your AR pistol running smoothly and reliably. After each shooting session, thoroughly clean the firearm. Disassemble the upper and lower receivers. Clean the bore of the barrel with a cleaning rod, brush, and appropriate solvent. Clean the bolt carrier group with a brush, solvent, and a pick. Lubricate the bolt carrier group with a quality gun oil. Inspect the entire firearm for wear, damage, or loose components.
Customization Options
Beyond maintenance, customization is one of the most exciting aspects of owning an AR pistol. Consider upgrading the sights or optics to improve accuracy. Experiment with different muzzle devices to manage recoil and muzzle flash. Explore various handguards to enhance the ergonomics and appearance. If you are legally able, consider different grips and foregrips. The possibilities are nearly endless.
Conclusion: The AR Pistol and the Journey of Building One
Building an AR pistol can be an enjoyable and rewarding experience that gives you a deeper understanding of the platform and allows you to create a firearm that is uniquely suited to your needs. This step-by-step guide has provided a thorough overview of the process, from understanding the legal requirements to the final test fire.
Remember to prioritize safety at every step of the process, and to respect the law. Always seek professional guidance when needed and, most importantly, be responsible and enjoy the journey.
Responsible gun ownership begins with education. Continue to research and educate yourself about your AR pistol and all other firearms.
