Mastering the Art of Building Your Own Firearm with 80% Lowers

The growing trend of building your own firearm has taken the gun community by storm, and one of the best places to start is with an 80% lower receiver. These partially finished components provide the perfect opportunity for gun enthusiasts to create a custom firearm tailored to their preferences. Whether you are new to firearms or an experienced enthusiast, working with an 80% lower opens up a world of possibilities in terms of cost-saving, learning, and personalizing your weapon. In this guide, we’ll explore the key benefits of 80% lowers, the legal considerations, and the step-by-step process of completing your firearm build.

What is an 80% Lower Receiver?

An 80% lower receiver is essentially a firearm part that is 80% finished, leaving 20% of the machining work for the builder to complete. It’s called an “80% lower” because it’s not yet fully machined and cannot be used as a functional firearm until it’s completed. These lowers are typically sold as unfinished pieces, usually for platforms like the AR-15, AR-10, or other similar rifles.

The main appeal of an 80% lower is that it is not classified as a firearm under federal law, which means it can be purchased without a background check or the need for an FFL (Federal Firearms License). However, once it’s completed, it becomes a firearm, and the owner must comply with all relevant laws, including serializing the firearm and adhering to state regulations.

Why Opt for an 80% Lower?

1. Personalization and Customization: One of the biggest reasons people choose to build their firearms from 80% lowers is the ability to fully customize their weapon. From the type of stock and handguard to the trigger system, using an 80% lower gives you the flexibility to create a firearm that perfectly suits your style and needs.

2. Learning and Skill Development: Building a firearm from an 80% lower offers a hands-on opportunity to learn more about how firearms work. For many, it’s a chance to enhance their technical skills in machining and assembly. Whether you’re using basic hand tools or more advanced equipment like a CNC machine, the process is a valuable learning experience that can teach you more about firearms and gunsmithing.

3. Cost-Effectiveness: An 80% lower can be significantly cheaper than buying a fully assembled firearm. This is especially true if you already have some of the required tools. By purchasing an 80% lower, you can save money on the receiver and use your budget to upgrade other parts of your firearm, like the barrel, bolt carrier group, or optics.

4. A Sense of Accomplishment: There’s an undeniable sense of pride in crafting your own firearm. Building it from the ground up and knowing each part was chosen by you gives a level of satisfaction that simply purchasing a firearm cannot provide. Whether you’re building for personal use or to add a custom piece to your collection, the process is a rewarding one.

Understanding the Legalities of 80% Lowers

Before diving into a firearm build, it’s essential to understand the legalities of 80% lowers, which can vary depending on your location:

• Federal Regulations: On a federal level, 80% lowers are not considered firearms because they aren’t yet fully completed. This means that when purchasing an 80% lower, you don’t need to undergo a background check, and it can be shipped directly to your door. However, once you finish machining the receiver, it becomes a firearm and must be treated as such under federal law.
• State-Specific Laws: While 80% lowers are legal in many states, several states have their own restrictions. States like California, New York, and New Jersey have stricter rules around the completion of these parts. In these states, you may be required to add a serial number or register your completed firearm with the state. Always check your local laws to avoid legal complications.
• Finishing the Lower: When you complete your 80% lower, you will need to ensure that it complies with your state’s laws. Some states might require you to add a serial number or complete specific registration steps before you can use your firearm legally.
• Selling or Transferring Firearms: If you plan to sell or transfer your completed firearm, you need to comply with all relevant federal and state laws, including any transfer requirements and background checks.

How to Complete an 80% Lower Receiver

The process of completing an 80% lower requires a few essential steps and the right set of tools. Here’s an overview of the key stages:

1. Choose the Right Tools: The tools you’ll need depend on how precise and detailed you want your build to be. At the minimum, you’ll need a drill press, jigs, drill bits, and files. For more accuracy, you might consider using a CNC machine to ensure that everything is cut to spec.

2. Select a Jig Kit: A jig kit is crucial for completing the lower receiver, as it guides you through the process of machining the receiver correctly. Most jigs are compatible with a standard drill press, and they will help you cut and drill the necessary holes for your firearm’s parts.

3. Milling the Fire Control Pocket: The fire control pocket is one of the most important parts of completing an 80% lower. This pocket holds the trigger mechanism and other internal components, so it must be cut accurately to ensure that everything functions correctly.

4. Drilling the Pin Holes: After milling the fire control pocket, you’ll need to drill holes for the pins that hold the trigger assembly and other parts in place. These holes must be precise to prevent issues with fitment and functionality.

5. Completing the Cuts: In addition to milling and drilling, you may also need to make other cuts, such as for the magazine well or buffer tube. These cuts can vary depending on the firearm platform you are working on, but precision is key.

6. Assemble the Firearm: Once the lower is complete, you can move on to assembling the rest of your firearm. Attach the upper receiver, trigger system, magazine catch, and any other parts. Be sure to test all parts before using the firearm to ensure everything is functioning properly.

Testing Your Finished Firearm

Once your firearm is assembled, it’s critical to test its function and safety before taking it to the range:

• Perform a Function Test: Before firing, run a function test to ensure all parts operate as expected. Check the trigger, magazine release, safety selector, and buffer tube.
• Professional Inspection: If you are new to gunsmithing, consider having your firearm inspected by a professional gunsmith before firing it. They can ensure the firearm is assembled correctly and meets safety standards.
• Test Fire in a Controlled Environment: When you’re ready to test fire your completed firearm, always do so in a safe and controlled environment, such as a shooting range. Make sure you’re using safety equipment, such as ear protection and safety glasses.

Pros and Cons of Using 80% Lowers

Before starting your project, it’s essential to weigh the pros and cons:

Pros:

• Great for customization and personalization of your firearm.
• A cost-effective way to build a firearm.
• Learn valuable gunsmithing skills.
• Privacy in building and owning a firearm.

Cons:

• Requires time, tools, and skill to complete the build.
• Legal complexities in some states.
• Requires attention to detail and precision to ensure the firearm functions correctly.

Conclusion: Should You Build with an 80% Lower?

Building a firearm with an 80% lower is a rewarding and educational experience that allows you to create a fully customized weapon. Whether you’re looking to save money, learn more about firearms, or simply enjoy the challenge of building your own gun, the 80% lower is an excellent starting point. However, be sure to consider the legal requirements, necessary tools, and time commitment before starting your build.

Ready to get started on your project? Visit 80-Lower.com to find a range of 80% lowers and kits to help you build your dream firearm.