The Rising Popularity of 80% Lowers: Why DIY Firearms Are Gaining Attention

In recent years, the world of firearm enthusiasts and hobbyists has witnessed a surge in the popularity of 80% lowers. These unfinished lower receivers allow individuals to build their own firearms from scratch, creating an unparalleled sense of accomplishment and customization. Whether you’re a seasoned gun enthusiast or a beginner looking to explore the world of DIY firearm construction, 80% lowers offer an exciting avenue for hands-on engagement.

In this blog, we will dive deep into the world of 80% lowers, covering the basics, legal considerations, the benefits and drawbacks of building your own firearms, and why they’ve become a hot topic among gun enthusiasts.

What Exactly Is an 80% Lower?

An 80% lower is a lower receiver for a firearm (typically an AR-15, AR-10, or similar) that is 80% finished. It requires additional machining or milling to make it fully functional. The key part of the firearm—the lower receiver—contains the trigger group, magazine well, and other essential components. An 80% lower is a “blank” or “unfinished” lower receiver, meaning that it lacks critical features like the fire control pocket (where the trigger mechanism sits) and the necessary holes for pins and bolts.

Because it’s not yet considered a fully functional firearm, the 80% lower doesn’t fall under the same legal regulations as completed firearms, such as mandatory background checks or serial number registration. The remaining 20% of machining work must be completed by the builder using the proper tools.

Why Is It Called an “80% Lower”?

The term “80% lower” refers to the fact that the lower receiver is 80% complete, meaning that it is partially finished but requires further work to be fully functional. While the receiver may look like a firearm part at first glance, it doesn’t qualify as a functional firearm until the remaining 20% of the machining process is completed.

It’s important to note that 80% lowers are not considered firearms by the ATF (Bureau of Alcohol, Tobacco, Firearms, and Explosives) until they are completed and assembled. This distinction is crucial in understanding why 80% lowers are subject to different legal requirements than fully functional firearms.

The Process of Completing an 80% Lower

Building a firearm from an 80% lower is an engaging and rewarding process that allows you to assemble a custom gun to your exact specifications. While the process can vary based on the type of firearm you’re building, there are a few general steps that are involved.

1. Gathering Tools and Materials

Before you begin, you’ll need a few essential tools to complete the lower. The most common tools used for building an 80% lower include:

Drill Press: A drill press is essential for drilling the necessary holes for the trigger, hammer, and safety pins.
Milling Machine: A milling machine is used to cut the fire control pocket, where the trigger mechanism will be installed.
Jig: A jig is a template that ensures the lower is positioned correctly for accurate drilling and milling.
Clamps: To hold the jig and the 80% lower securely during machining.
Measuring Tools: Accurate measuring tools like calipers and rulers are necessary to ensure everything is done to proper specifications.

2. Setting Up the Jig

The first step in completing an 80% lower is to secure the lower receiver in a jig. The jig will guide you as you drill holes and mill the fire control pocket. Proper alignment of the lower receiver and jig is crucial to ensure the firearm is functional and safe to operate.

3. Drilling the Pin Holes

The lower receiver needs several pin holes drilled to allow for the trigger, hammer, and safety components to be installed. The jig typically includes templates or guides that show the correct placement of the holes. You will use the drill press to drill these holes with precision.

4. Milling the Fire Control Pocket

This is the most critical step in completing an 80% lower. The fire control pocket is where the trigger mechanism, hammer, and other internal components will fit. Using a milling machine, you’ll need to mill out the fire control pocket to the precise dimensions outlined in the jig. This step requires patience and attention to detail, as any mistakes could render the lower receiver unusable.

5. Deburring and Polishing

Once the milling and drilling are completed, you may find that there are rough edges or burrs that need to be smoothed out. Deburring tools or files are used to remove these imperfections. This step ensures that the lower receiver will function properly and that the sharp edges won’t interfere with the installation of components.

6. Final Assembly

Once the 80% lower is fully machined, the next step is to install all the internal components—such as the trigger, hammer, and safety selector—along with the external components like the stock and buffer tube. At this point, the lower receiver is considered a completed firearm.

Legal Considerations for 80% Lowers

While the process of building a firearm from an 80% lower is legal in many parts of the United States, there are several legal considerations that must be understood before you begin the build. Laws vary at the federal, state, and local levels, so it’s crucial to familiarize yourself with these regulations to ensure you are in compliance.

Federal Regulations

At the federal level, an 80% lower is not classified as a firearm because it requires further machining before it can function as a gun. This means that when purchasing an 80% lower, you do not need to undergo a background check, and the purchase does not require a serial number.

However, once the lower is completed and assembled into a functional firearm, it is considered a firearm under federal law. As such, it must have a serial number and be registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF).

Additionally, ghost guns, or firearms that do not have serial numbers, have been the subject of increased scrutiny in recent years. The ATF has issued clarifications stating that the act of building a functional firearm from an 80% lower does not violate federal law, provided the necessary steps are followed, including marking the firearm with a serial number.

State and Local Laws

State and local laws regarding 80% lowers vary widely. Some states have enacted stricter laws around the use, purchase, and completion of 80% lowers. For example:

California: California has strict laws regarding ghost guns, and it requires 80% lowers to be serialized before completion. Additionally, the state has outlawed the purchase of 80% lowers unless the buyer has a federal firearms license (FFL).
New York: In New York, it’s illegal to possess an unfinished firearm receiver, including 80% lowers, without being registered as a firearms manufacturer.
New Jersey: Similar to California and New York, New Jersey has laws that regulate the purchase and possession of 80% lowers, requiring serialization and proper registration.

It’s essential to consult the laws in your state and local jurisdiction before purchasing or completing an 80% lower to ensure you comply with all applicable regulations.

Advantages of Building a Firearm from an 80% Lower

There are several reasons why individuals choose to build their own firearms from 80% lowers. Below are some of the primary advantages:

1. Customization

Building your own firearm allows for complete customization. From the type of trigger to the barrel length, you can select every component to suit your preferences. This gives you the freedom to create a weapon that is uniquely yours.

2. Cost Savings

In many cases, building a firearm from an 80% lower can be more cost-effective than purchasing a fully assembled firearm. You can source parts separately, which may result in lower overall costs compared to buying a pre-built gun from a store.

3. Learning Experience

Assembling a firearm from an 80% lower is an educational experience. You’ll learn the ins and outs of how firearms function, giving you valuable knowledge that can help with future builds, maintenance, and troubleshooting.

4. Satisfaction and Pride

Completing a firearm from scratch provides a sense of accomplishment. It’s a rewarding project that allows you to take pride in the work you’ve done and the finished product you’ve created.

Drawbacks of 80% Lowers

While building a firearm from an 80% lower offers many benefits, there are also some drawbacks to consider:

1. Time and Effort

Completing an 80% lower is a time-consuming process that requires precision and attention to detail. For beginners, the task may seem overwhelming, and mistakes can be costly.

2. Legal Complexity

As discussed earlier, legal regulations around 80% lowers vary by jurisdiction, and laws are constantly evolving. Staying informed about the legal landscape is crucial to avoid any legal pitfalls.

3. Tooling Costs

The tools needed to finish an 80% lower, such as milling machines and drill presses, can be expensive. If you don’t already have access to these tools, you may need to invest in them, which can increase the overall cost of the project.

Conclusion

80% lowers offer a unique and rewarding opportunity for firearm enthusiasts to build custom firearms that suit their personal needs and preferences. The process of completing an 80% lower requires precision and knowledge, but the result is a firearm that you’ve built from the ground up, giving you total control over the design and function.

However, it’s essential to navigate the legal complexities surrounding 80% lowers carefully. With varying state laws and evolving federal regulations, always ensure that you are in full compliance with your local laws.

For those willing to put in the time and effort, building a firearm from an 80% lower can be an incredibly fulfilling and cost-effective project. Whether you’re looking to personalize your gun or simply enjoy the experience of crafting your own weapon, 80% lowers provide an exciting and customizable route to DIY firearm ownership.