The Complete Guide to 80% Lowers: What You Need to Know

In recent years, 80% lowers have become a popular topic among firearm enthusiasts and hobbyists alike. These unassembled receivers allow gun owners to build their firearms from the ground up, often offering greater customization, potential savings, and a deeper understanding of how firearms operate. But what exactly is an 80% lower, and why is it so popular?

In this article, we will delve deep into the world of 80% lowers. We’ll cover everything from what they are, how they work, the legal aspects surrounding them, and why so many gun owners are choosing to build their own firearms. By the end of this guide, you’ll have a comprehensive understanding of 80% lowers and how to safely and legally build a firearm using one.

What is an 80% Lower?

An 80% lower refers to a firearm receiver that is 80% complete. This means that it has not been fully machined to the point where it can legally function as a firearm. The remaining 20% of the machining process must be completed by the owner or builder using tools and techniques like milling, drilling, or other methods of custom fabrication.

The term “lower” refers to the lower receiver of a firearm, which is a critical component that houses the trigger, hammer, and magazine well. This part is crucial to the operation of a firearm. While the term “80% lower” is most often associated with AR-15-style rifles, it can apply to a variety of different firearms, including AR-10 rifles, pistols, and even shotguns.

How Do 80% Lowers Work?

The 80% lower is typically sold as a raw, unfinished piece of metal—usually aluminum or steel. The buyer then completes the final machining and assembly work to make it fully functional. This process usually involves drilling specific holes, cutting certain areas, and ensuring the part is properly shaped to fit the other components of the firearm.

Once you complete the necessary machining, the 80% lower becomes a functioning firearm receiver that can be used to build a complete firearm. The process may sound complex, but with the right tools and guidance, it can be an enjoyable and rewarding project.

Why Choose to Build with an 80% Lower?

There are several reasons why gun enthusiasts choose to build their firearms using an 80% lower instead of purchasing a fully assembled firearm. Here are some of the most common reasons:

1. Customization

When you build a firearm from an 80% lower, you have complete control over its configuration. You can choose every part, from the type of barrel to the stock, trigger, and even the type of finish you want. This level of customization allows you to create a firearm that fits your exact needs, whether it’s for hunting, self-defense, or recreational shooting.

2. Cost Savings

Building a firearm from an 80% lower can be more affordable than purchasing a fully assembled firearm. Although the upfront cost of the lower receiver may be higher than purchasing a complete rifle, you can save money in the long run by sourcing parts individually and assembling them yourself.

3. Learning Experience

Building a firearm from scratch is a fantastic way to learn about how firearms operate. Assembling a firearm from an 80% lower will give you a deeper understanding of its internal components and how each part contributes to the overall functionality of the gun. This knowledge can be invaluable for troubleshooting, repairs, or upgrades in the future.

4. Legal Considerations

In some jurisdictions, purchasing an 80% lower and completing the build yourself can be a way to avoid certain legal restrictions that apply to fully assembled firearms. While you are still required to follow all relevant federal and state laws, the legal framework surrounding 80% lowers is often more lenient than it is for fully manufactured firearms.

5. Satisfaction of Building Your Own Firearm

There’s an inherent satisfaction in building something with your own hands, and a firearm is no exception. For many gun owners, assembling a firearm from an 80% lower is not just about functionality—it’s about the pride of craftsmanship and the joy of making something truly unique.

Legal Considerations for 80% Lowers

One of the most important aspects of 80% lowers is their legal status. While the process of buying and using 80% lowers is perfectly legal in many parts of the United States, it is not without regulation. It’s crucial for anyone interested in purchasing an 80% lower to fully understand the legal landscape surrounding these parts to ensure compliance with all applicable laws.

Federal Regulations

At the federal level, 80% lowers are legal to purchase, sell, and own. According to the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), an 80% lower receiver is not classified as a firearm because it lacks the necessary features to be considered a functional gun. Since it is not yet a complete firearm, it is not subject to the same regulations as fully assembled firearms.

However, once you complete the final machining and the 80% lower becomes a fully functioning receiver, it is subject to all the laws that apply to firearms. For example, if you plan to sell the firearm or transfer ownership, you may need to go through a background check and other procedures depending on your jurisdiction.

State Laws

State laws regarding 80% lowers vary widely. In some states, 80% lowers are legal to purchase and build, while in others, the process is heavily restricted or outright banned. Some states require that you register the completed firearm with local authorities, while others do not. It’s essential to research your state’s specific laws before purchasing or building with an 80% lower.

For example, California, New Jersey, and New York have stringent restrictions on 80% lowers, while states like Texas and Arizona have fewer regulations regarding their purchase and use. Be sure to consult local laws and, if necessary, seek legal advice to ensure you comply with all applicable regulations.

No Serial Numbers and Homemade Firearms

One of the more controversial aspects of 80% lowers is the lack of serial numbers. Firearms are typically required by law to have a serial number, which is used for identification purposes. However, 80% lowers are not considered firearms until they are completed, which means they do not have serial numbers when purchased.

When you finish building your firearm from an 80% lower, you are not required by federal law to affix a serial number. However, some states may have different requirements, so it’s crucial to check the laws in your area. If you’re ever in doubt, it may be wise to apply for a serial number from the ATF to ensure you’re complying with the law.

How to Build a Firearm with an 80% Lower

Building a firearm from an 80% lower requires several steps and specialized tools. While the process can seem daunting at first, it’s manageable with the right knowledge and preparation. Here’s a general outline of how to go about it:

1. Gather Your Tools and Materials

The first step is to gather all the tools and materials you’ll need. Depending on the type of firearm you’re building, you’ll likely need a drill press, a jig (a template that guides your cuts), a milling machine or router, and various cutting tools like end mills and drill bits.

In addition to the 80% lower itself, you’ll also need other components like the upper receiver, barrel, trigger group, stock, and magazine. Many manufacturers offer 80% lower kits that include all the necessary components, along with the tools to complete the build.

2. Prepare the 80% Lower

Next, you’ll need to prepare the 80% lower for machining. This typically involves setting it up in the jig to ensure that everything is aligned correctly. The jig serves as a guide to make sure you drill and mill the correct holes in the right places.

3. Drill and Mill the Necessary Holes

Using your tools, carefully drill and mill the necessary holes and cuts in the 80% lower. This step is crucial, as the holes must be precise in order for the parts to fit together properly and for the firearm to function correctly.

4. Assemble the Firearm

Once the lower receiver is fully machined, you can begin assembling the firearm by adding components such as the upper receiver, barrel, trigger assembly, and other parts. Follow the manufacturer’s instructions carefully to ensure everything is assembled properly.

5. Test the Firearm

Before using your newly built firearm, it’s essential to test it for functionality and safety. Perform a thorough check to ensure all parts are secure, the action works smoothly, and there are no defects. If you’re unfamiliar with firearm assembly, it may be a good idea to seek professional assistance or have a gunsmith inspect your work.

Potential Risks and Considerations

While building a firearm from an 80% lower can be a rewarding project, it is not without risks. Here are a few things to keep in mind:

• Machining Accuracy: Precision is critical when building a firearm. If you make an error during the machining process, it could result in a malfunctioning firearm or one that is unsafe to use.
• Legal Compliance: As mentioned earlier, it’s essential to ensure you’re following all local, state, and federal laws when purchasing and building a firearm from an 80% lower.
• Time and Effort: Building a firearm from scratch requires a significant time investment. The process can be tedious, and mistakes may require rework or the replacement of parts. Make sure you’re prepared for the time commitment before beginning.

Conclusion

80% lowers offer gun enthusiasts the chance to build their firearms from the ground up, providing a unique blend of customization, learning, and satisfaction. While the process of building a firearm from an 80% lower requires precision, effort, and careful consideration of legal requirements, it can be incredibly rewarding for those who enjoy hands-on projects and want a deeper understanding of firearms.

If you’re thinking about building a firearm from an 80% lower, make sure to educate yourself thoroughly on the process, gather the necessary tools, and always adhere to local, state, and federal laws. By doing so, you’ll be well on your way to creating a functional and personalized firearm that meets your specific needs.