Assembling an AR-style lower receiver is a rewarding experience for firearm enthusiasts and DIY builders alike. This foundational component of the AR-15 platform houses critical mechanisms that control the rifle’s function. In this comprehensive guide, we will walk you through the essential steps for assembling an AR-style lower correctly, ensuring both safety and performance.
Contents
Understanding the AR-Style Lower Receiver
The AR-style lower receiver is a key element in the functionality of an AR-15 or similar rifle. It houses the trigger mechanism, magazine well, and the buffer tube that connects to the stock. Typically made from aluminum, the lower receiver is serialized and considered the firearm by legal standards—this means it requires proper handling and sometimes registration, depending on local laws.
Necessary Tools and Parts
Before starting the assembly, gather the required tools and parts:
Tools
- Punch set: For driving in pins.
- Hammer: A lightweight hammer works best.
- Torque wrench: For securing the buffer tube.
- Pliers: Needle-nose pliers can be handy.
- Cleaning cloth: To keep parts free from debris.
Parts
- Lower receiver: The serialized main body.
- Lower parts kit (LPK): Includes the trigger, disconnect, hammer, and springs.
- Stock and buffer tube assembly: For the rear of the lower.
- Pistol grip: To provide a hold on the firearm.
- Trigger guard: To protect your trigger mechanism.
Step-by-Step Assembly Process
Step 1: Prepare the Workspace
Before starting, ensure that your workspace is clean, well-lit, and organized. Lay out ar15 lower tools and parts so that you can easily access them as you work. A flat surface will help prevent any pieces from rolling away.
Step 2: Install the Trigger
- Locate the trigger slot: Identify the trigger pocket in the lower receiver.
- Insert the trigger: Position the trigger in the slot, ensuring the hole for the trigger pin lines up.
- Install the trigger pin: Use a punch to drive the trigger pin through both sides until fully seated.
- Add the trigger spring: Insert the spring into the rear of the trigger mechanism.
Step 3: Attach the Hammer
- Position the hammer: Insert the hammer into the lower receiver, aligning it with the hammer pin hole.
- Install the hammer pin: Similar to the trigger, use a punch to drive the hammer pin through both sides, securing it in place.
- Set the hammer spring: Ensure that the hammer spring is positioned correctly, providing tension against the hammer.
Step 4: Insert the Disconnector
- Insert the disconnector: This component sits atop the trigger and should be aligned with its corresponding cutout in the lower receiver.
- Secure the disconnector spring: The spring must be placed in the designated cavity of the disconnector, allowing it to return to position after being activated.
Step 5: Install the Pistol Grip
- Select the grip: Choose your pistol grip from your kit.
- Align the grip: Position the grip over the designated screw hole.
- Secure the grip: Insert the screw and tighten it until snug but not overly tight, allowing for any necessary adjustments later.
Step 6: Attach the Trigger Guard
- Position the trigger guard: Align it with the corresponding holes at the rear of the magazine well.
- Insert the roll pin: Use the punch set to carefully tap in the roll pin without damaging the driver.
- Check for movement: Ensure the trigger guard is firmly secured but can still pivot if necessary.
Step 7: Install the Stock and Buffer Tube
- Secure the buffer tube: Screw the buffer tube into the lower receiver, using a torque wrench to ensure it’s adequately tightened. Most receivers have a recommended torque specification.
- Insert the buffer and spring: Place the buffer spring into the buffer tube, followed by the buffer itself, ensuring that it moves smoothly.
Step 8: Perform Final Checks
- Function test: Before anything else, conduct a function test to ensure all components are working correctly. Pull the trigger to test the reset.
- Safety check: Confirm that the safety selector functions smoothly and adequately engages both safe and fire positions.
- Visual inspection: Inspect your work for any loose parts or misaligned pieces.
Step 9: Cleaning and Maintenance
Finally, clean the lower receiver and the interior components with a suitable gun-specific cleaner to remove any oils or fingerprints. This step is vital for maintaining the longevity and functionality of your build.
Conclusion
Assembling an AR-style lower receiver is an enriching experience that enhances your understanding of the firearm’s mechanics. By following the above steps and adhering to safety and legal considerations, you’ll create a reliable foundation for your AR-15 or similar platform. Take your time, and don’t rush the process—precision and attention to detail are the keys to a successful build. Once completed, enjoy your new firearm, knowing that you built it from the ground up!