From Blank to Bang: Completing Your 80% Lower Receiver at Home
How to Build 80 Lower Receiver: Top Steps for 2024
Get Started with Building Your 80% Lower Receiver
If you’re curious about how to build an 80 lower receiver, you’re in the right place. An 80% lower receiver is a partially milled lower receiver for firearms, most commonly used in AR-style rifles. It’s a popular choice among firearms enthusiasts because it allows for a DIY project without the need for an FFL (Federal Firearms License) or additional paperwork. Below, you’ll find a quick outline to get you started right away:
- Acquire an 80% lower receiver.
- Gather necessary tools: Drill press, router, jigs, cutting fluid, etc.
- Set up your workspace: Ensure safety and proper setup.
- Drill initial holes: Proper measurements and depth settings are crucial.
- Mill the fire control pocket: Achieve precision with end mills.
- Finish and assemble: Sand, file, test fit, and install parts.
Building your own 80% lower receiver can be incredibly rewarding. It offers you a hands-on experience to understand the mechanics of your firearm fully. You also get the unique satisfaction of crafting a custom rifle or pistol to your exact specifications.
However, it’s crucial to understand the legal considerations. Federally, an 80% lower is not considered a firearm until completed, so no FFL is required. But once finished, it must comply with federal regulations, and you must check your state laws to ensure compliance.
Ready to dive in? Let’s walk through the process step-by-step.
Understanding 80% Lower Receivers
Definition
An 80% lower receiver is a partially milled lower receiver for a firearm, most commonly for AR-style rifles. The term “80%” comes from the fact that it is 80% complete, leaving the remaining 20% of the machining process to be done by the buyer. This unfinished state means it lacks the necessary machining to function as a firearm, specifically the fire control group area.
Legal Status
From a federal standpoint, an 80% lower receiver is not considered a firearm. This means you can purchase and ship it directly to your door without the need for a Federal Firearms License (FFL) or background check. However, once you complete the milling and drilling, it transforms into a firearm and must comply with all federal laws, including serialization and registration where required.
Important: Always check your state and local laws before starting your build. States like California, New York, and New Jersey have specific restrictions or outright bans on 80% lowers. For instance, California requires serialization even on unfinished lowers.
Types
There are several types of 80% lower receivers, each with unique characteristics and materials:
- Billet Lower Receivers
- Made from solid blocks of aluminum (usually 6061-T6 or 7075-T6).
- Offers high customization options.
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6061-T6 is easier to mill and more corrosion-resistant, while 7075-T6 is harder and more durable.
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Forged Lower Receivers
- Created by hammering aluminum into shape.
- Generally considered more robust and durable.
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Often used for “mil-spec” builds.
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Polymer Lower Receivers
- Made from high-strength polymer.
- Lighter and easier to mill than aluminum.
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Often less durable but sufficient for many builds.
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Cast Lower Receivers
- Made by pouring molten aluminum into a mold.
- Typically less robust than forged or billet but still functional for many builds.
Choosing the right type depends on your specific needs, the tools you have, and your experience level.
Key Points to Remember
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Customization: One of the significant benefits of using an 80% lower is the ability to customize your firearm to your exact specifications. This includes adding personal touches like custom logos, colors, and finishes.
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Privacy: Since you can buy an 80% lower without a background check in most states, it offers a level of privacy that is appealing to many firearm enthusiasts.
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Cost-Effective: Building your own firearm can often be more affordable than purchasing a pre-built one.
Understanding these basics will set you on the right path as you learn how to build an 80% lower receiver.
Ready to gather your tools? Let’s move on to the next section: How to Build 80 Lower Receiver: Tools and Materials.
How to Build 80 Lower Receiver: Tools and Materials
Before diving into the milling process, it’s crucial to gather all the necessary tools and materials. This ensures you have everything you need right at your fingertips, making the build smoother and more efficient.
Essential Tools
Drill Press
A drill press is indispensable for this project. It helps create precise holes and can handle the stress of milling. The bigger and heavier, the better. However, even a small, basic model can get the job done.
- Tip: Run the drill press at the slowest speed possible and use a light hand to avoid overheating and damaging the material.
Hand Tools
Hand tools are also vital for fine-tuning and finishing touches. Key tools include:
- C-clamps: Essential for securing your workpiece. Bigger clamps offer better stability.
- Hand files: Useful for smoothing out rough edges and ensuring a snug fit for all parts.
- Hammer: Needed for testing the fit of the trigger, hammer, and safety selector.
Dremel
The Dremel tool is your best friend for detailed work. Equipped with a sanding drum and a 1/8-inch rotary rasp, it helps smooth out the fire control pocket and other tight areas.
- Tip: Use a light touch to avoid removing too much material.
Jigs
An 80-percent jig is a must-have for guiding your drill and ensuring precision. It holds your lower receiver in place and provides a template for drilling and milling.
- Tip: Invest in a high-quality jig to make your work easier and more accurate.
Cutting Fluid
Using cutting fluid like WD-40 on aluminum helps keep your drill bits cool and prolong their life. It also makes the milling process smoother by reducing friction.
- Tip: Apply cutting fluid generously and frequently to keep the material cool and prevent clogging.
Summary Table
| Tool | Purpose |
|---|---|
| Drill Press | Precise holes and milling |
| Hand Tools | Fine-tuning and smoothing edges |
| Dremel | Detailed work and smoothing tight areas |
| Jigs | Guide for drilling and ensuring precision |
| Cutting Fluid | Keeps drill bits cool and reduces friction |
With these tools and materials, you’re well-prepared to start your journey of learning how to build an 80 lower receiver.
Next, we’ll walk you through the step-by-step guide to milling your 80% lower. Ready to get started? Let’s move on!
Step-by-Step Guide to Milling Your 80% Lower
Preparing Your Workspace
Before you begin, safety is your top priority. Always wear safety glasses and gloves to protect yourself from metal shavings and sharp edges.
Setup your workspace in a well-lit, clean area. Ensure your drill press or milling machine is stable and has enough room for maneuvering your 80% lower receiver.
Clamping is crucial. Use C-clamps to secure your jig and receiver firmly to the drill press table. This prevents movement and ensures precision. Double-check that everything is tight before you start drilling.
Drilling the Initial Holes
Start by measuring and marking the locations for the initial holes. Use a steel rule or calipers for accuracy.
Insert a 5⁄16-inch drill bit into the chuck and tighten well. With the drill press off, touch the tip of the drill to the top of the receiver to set the depth of cut. Aim for a depth of 1 1⁄8 inches from the top of the receiver.
Peck drilling is a technique where you drill in short bursts, lifting the bit frequently to clear away chips and reduce heat buildup. This ensures cleaner cuts and prolongs the life of your drill bits.
Milling the Fire Control Pocket
Swap the drill bit for a 5⁄16-inch two-flute, center-cutting end mill. Set the depth of cut 1⁄8-inch deeper, to 1¼ inches.
Material removal should be done slowly and steadily. Run the drill press at its slowest speed and use a light hand. Squirt some cutting fluid to keep the bit cool and reduce friction.
Use the end mill to hog out the fire control pocket. Follow the outline marked in your jig, moving the end mill around the pocket to remove as much material as possible.
Finishing Touches
After milling, it’s time for the finishing touches. Use a Dremel with a sanding drum and a 1⁄8-inch rotary rasp to smooth out any rough edges inside the fire control pocket.
Hand files are excellent for fine-tuning. Carefully file down any high spots or burrs until the surfaces are smooth.
Testing fit is crucial. Insert the hammer, trigger, and safety selector to ensure they fit properly. If anything is too tight, gently file down the areas until everything fits snugly.
Sanding the entire lower receiver will give it a polished look. Use fine-grit sandpaper to remove any remaining rough spots.
With these steps, you’ve successfully milled your 80% lower receiver! Next, we’ll move on to the assembly and customization phase to complete your build.
How to Build 80 Lower Receiver: Assembly and Customization
Now that you’ve milled your 80% lower receiver, it’s time for assembly and customization. This part involves installing the trigger, safety selector, pins, and buffers. Let’s break it down step-by-step.
Trigger Installation
1. Gather Your Tools and Parts
You’ll need:
– Trigger
– Trigger spring
– Disconnector
– Disconnector spring
– Trigger pin
– Small hammer
– Punch set
2. Assemble the Trigger Group
Start by placing the trigger spring onto the trigger. Ensure the spring legs are facing forward. Next, attach the disconnector to the trigger using the disconnector spring.
3. Install the Trigger
Position the trigger group into the lower receiver’s trigger pocket. Align it with the trigger pin holes. Use a punch to help guide the trigger pin through the holes. Tap the pin gently with a hammer until it’s flush.
4. Test the Trigger
Pull the trigger a few times to ensure it moves freely. The trigger should reset properly with each pull.
Safety Selector Installation
1. Insert the Safety Selector
Slide the safety selector into its designated hole on the side of the lower receiver.
2. Add the Detent and Spring
Place the detent into the small hole next to the safety selector. Then, insert the spring into the same hole.
3. Attach the Pistol Grip
Align the pistol grip with the lower receiver, making sure the spring fits into the grip’s hole. Secure the grip with a screw. This will keep the detent and spring in place.
4. Test the Safety Selector
Switch between “SAFE” and “FIRE” to ensure the safety selector moves smoothly and locks into position.
Pin Installation
1. Hammer Pin and Trigger Pin
You’ve already installed the trigger pin. Now, install the hammer and its spring. Place the hammer into its pocket and align it with the hammer pin holes. Use a punch to guide the hammer pin through and tap it with a hammer until it’s flush.
2. Test the Pins
Ensure both the hammer and trigger move freely and reset correctly. If anything feels tight, gently file the pinholes.
Buffer Installation
1. Attach the Buffer Tube
Screw the buffer tube into the back of the lower receiver. Insert the buffer detent and spring into the hole at the bottom of the tube.
2. Secure with Castle Nut and Latch Plate
Slide the latch plate over the buffer tube, followed by the castle nut. Tighten the castle nut using an armorer’s wrench to secure the buffer tube.
3. Insert the Buffer and Spring
Place the recoil spring into the buffer tube, followed by the buffer. Push them in until the buffer detent locks them in place.
4. Test the Buffer Assembly
Ensure the buffer and spring move freely within the tube. This will help in absorbing recoil during shooting.
By following these steps, you’ve successfully assembled and customized your 80% lower receiver. Next, we’ll address some frequently asked questions about building 80% lowers.
Frequently Asked Questions about Building 80% Lowers
Is it legal to make an 80% lower?
Yes, it is legal to manufacture an 80% lower receiver into a fully functional firearm for personal use under federal law. The Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) does not consider an 80% lower to be a firearm, so it can be shipped directly to your door without the need for a Federal Firearms License (FFL) or background check. However, state laws may vary, so it’s crucial to check your local regulations before starting your build. For instance, some states have banned AR-15 kits and certain parts, so always verify local laws to ensure compliance.
Do 80% lowers need to be serialized?
No, 80% lowers do not need to be serialized under federal law. When you complete the milling process, the firearm is intended for personal use and does not require a serial number. However, if you intend to sell or transfer the firearm, federal law requires it to be serialized. Some states have their own requirements regarding serialization, even for personal use, so it’s essential to check state-specific regulations. For example, California mandates serialization and background checks for homemade firearms. Always stay informed about your local laws to avoid legal complications.
How deep to drill 80 lower?
Drilling the fire control pocket in an 80% lower requires precision. The typical depth for the fire control pocket is 1.25 inches, but this can vary slightly depending on the specific lower and jig you’re using. Always refer to the manufacturer’s guidelines for exact measurements.
Steps for Accurate Drilling:
1. Use a Drill Press or Milling Machine: Ensure your machine is calibrated correctly.
2. Peck Drilling: Drill in small increments to maintain control and accuracy.
3. Check Depth Frequently: Use a caliper to measure the depth as you go.
By following these guidelines, you can achieve the precise depth required for a functional fire control pocket.
Ready to dive deeper? Let’s move on to the next section where we’ll explore the assembly and customization of your 80% lower receiver.
Conclusion
Building an 80% lower receiver at home can be a rewarding and educational experience. It allows you to create a custom AR-15 tailored to your preferences and needs. But before we wrap up, let’s review some key points and safety reminders.
Review
What We’ve Covered:
– Understanding 80% Lower Receivers: We explained what an 80% lower is and its legal status.
– Tools and Materials: We discussed the essential tools like drill presses, jigs, and cutting fluid.
– Step-by-Step Guide: From preparing your workspace to drilling and milling, we provided detailed instructions.
– Assembly and Customization: We walked through installing triggers, safety selectors, and other components.
By following these steps, you can turn a blank 80% lower receiver into a fully functional lower assembly.
Safety Reminders
Safety cannot be overstated when building your 80% lower receiver.
Important Safety Tips:
– Always Wear Safety Gear: Safety glasses, gloves, and hearing protection are a must.
– Secure Your Workspace: Ensure all tools and materials are stable and secure to prevent accidents.
– Follow Instructions Carefully: Precision is key. Rushing through steps can lead to mistakes or injuries.
– Double-Check Legal Requirements: Make sure you comply with all local, state, and federal laws regarding homemade firearms.
Why Choose Daytona Tactical?
At Daytona Tactical, we offer everything you need to complete your 80% lower receiver build. Our comprehensive selection of 80% lower receivers and build kits are designed to make your DIY project as smooth and enjoyable as possible.
Why Us?
– Quality Products: We provide high-quality, durable parts that you can rely on.
– Expert Support: Our team is here to help you with any questions or challenges you might face.
– Comprehensive Guides: From detailed tutorials to expert tips, we ensure you have all the information you need.
Ready to start your build? Visit our 80% lower receivers page to get started.
Building an 80% lower receiver is not just about creating a firearm; it’s about the pride and satisfaction that comes with crafting something with your own hands. Stay safe, follow the guidelines, and enjoy the process!
Feel free to reach out to us with any questions or for further assistance. Happy building!
