In recent years, 80% lowers have become a highly sought-after component for gun enthusiasts and hobbyists looking to build custom firearms. The term “80% lower” refers to a partially completed receiver that requires further machining to become a functional firearm lower receiver. The beauty of 80% lowers is that they allow individuals to assemble their own firearms at home, often without the need for federal firearms licenses, provided that local laws are adhered to. This guide explores everything you need to know about 80% lowers, including their legal status, their uses, how to build with them, and much more.
What Is an 80% Lower?
An 80% lower is a firearm lower receiver that has been partially finished but still requires further work to become a functional firearm. The lower receiver is the part of the gun that houses the trigger mechanism, magazine well, and pistol grip. While the 80% lower is not yet classified as a firearm, it can be transformed into one with the proper tools and knowledge.
The 80% designation means that the lower receiver is 80% complete; it has been pre-machined in several key areas but lacks the necessary holes, cuts, and finishing touches that are required for it to operate as part of a functioning firearm. These components are typically sold as kits that provide everything needed to complete the lower receiver.
Why Are 80% Lowers Popular?
There are several reasons why 80% lowers are popular among gun enthusiasts and builders:
- Legality: As mentioned earlier, an 80% lower is not considered a firearm by the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) because it is not yet fully functional. This makes it legal to purchase without background checks or serial numbers in many places, although local laws may vary.
- Customization: 80% lowers give gun builders the ability to customize their firearms to their exact specifications. Builders can choose the type of material, finish, and design they prefer, creating a truly personalized firearm.
- Privacy: Building a firearm from an 80% lower provides more privacy compared to buying a pre-manufactured firearm. The finished product does not have a serial number, making it untraceable.
- Cost-Effective: In many cases, building a firearm from an 80% lower can be more affordable than purchasing a complete, factory-made gun. Builders can select parts based on their budget and preferences.
- Skill Development: Building a firearm from an 80% lower provides an opportunity to learn about firearm mechanics and assembly. Many hobbyists enjoy the challenge of completing a partially finished product.
How Do You Build With an 80% Lower?
Building a firearm using an 80% lower receiver involves several steps. The following guide will walk you through the general process of building a firearm from an 80% lower.
Step 1: Gather Necessary Tools
Before you begin, you will need to gather the tools required for completing the 80% lower. These typically include:
- Drill press or hand drill: To drill the necessary holes.
- End mills: To cut the receiver’s internal features.
- Vice: To hold the receiver steady during machining.
- Jig: A jig is a guide that helps you correctly align and drill the necessary holes.
- Measuring tools: To ensure proper dimensions.
The required tools can vary depending on the type of 80% lower you are working with (e.g., AR-15, AR-10, Glock frame, etc.), so be sure to check the instructions provided with the kit.
Step 2: Prepare the 80% Lower
Your 80% lower will likely come with a partially machined receiver and a jig. The jig is used to align the 80% lower and make sure the holes and cuts are made in the correct locations. Start by securing the 80% lower into the jig. It is crucial to follow the instructions carefully to ensure that the receiver is aligned correctly for machining.
Step 3: Drill and Mill
Using the drill press or hand drill, drill out the necessary holes for the trigger group, fire control group, and other important components. This step is the most critical part of completing your 80% lower. Use the correct drill bit sizes for each hole to ensure everything aligns properly.
Once the holes are drilled, you will need to mill the internal parts of the receiver, such as the fire control pocket and the magazine well. This step requires precise cutting, and most builders use end mills to perform this task. Some kits come with the necessary milling bits, but others may require you to purchase additional tools.
Step 4: Check Functionality
Once you have completed the necessary milling and drilling steps, it’s essential to check that the components of your firearm fit correctly. Insert the trigger, hammer, and other parts into the lower receiver to ensure that everything fits and operates smoothly. If you encounter any issues, carefully check the dimensions and alignment of the parts.
Step 5: Finish the Lower
After completing the lower receiver, you can apply your desired finish. This could include anodizing, Cerakote, or simply polishing the surface. The finishing process is not just cosmetic; it also helps protect the metal from corrosion.
Step 6: Assemble the Firearm
Once your 80% lower is finished, you can begin assembling the rest of the firearm. Depending on the type of gun, you will need additional components like the upper receiver, barrel, and stock. Follow the specific assembly instructions for your firearm to ensure a functional build.
Legal Considerations for 80% Lowers
While 80% lowers are legal in many areas, it’s important to understand the legal implications of building a firearm from one. In the United States, the ATF does not regulate the sale or possession of 80% lowers because they are not considered firearms until they are fully completed. However, once the 80% lower is finished, it may be subject to firearm laws.
Here are a few things to keep in mind:
- No Serial Numbers: Since 80% lowers do not have serial numbers, they are not traceable by the authorities. Some states and local jurisdictions may require you to mark the firearm with a serial number once it is completed.
- Building for Personal Use: It is legal to build a firearm for personal use in most states, but it is illegal to sell or transfer a firearm built from an 80% lower without going through the proper legal channels.
- Federal Laws: Although 80% lowers are not regulated by the ATF, once you complete the lower receiver, the firearm may be subject to federal laws, including background checks for transfers and prohibited persons (e.g., felons, domestic abusers).
- State and Local Laws: Many states have specific regulations concerning 80% lowers. Some have passed laws that require background checks for the purchase of 80% lowers, while others have outright banned them. It’s essential to check local laws before buying or building with an 80% lower.
Types of 80% Lowers
There are several types of 80% lowers available, each designed for a different type of firearm. Some of the most common 80% lowers include:
1. AR-15 80% Lowers
The AR-15 platform is one of the most popular firearms in the United States. The AR-15 80% lower is one of the most commonly built and used 80% lowers, primarily due to the platform’s modularity and ease of customization. The AR-15 80% lower typically requires milling and drilling to complete.
2. AR-10 80% Lowers
The AR-10 is another popular platform, primarily chambered in .308 caliber. The AR-10 80% lower is larger than the AR-15 counterpart and requires similar steps to complete. Builders often choose the AR-10 for its greater stopping power and longer-range capabilities.
3. Glock 80% Lowers
Glock 80% lowers are designed for people who want to build their own Glock pistol. These lowers come in the form of polymer or metal frames and require significant work to finish. Building a Glock from an 80% lower allows for a high level of customization, including grip texture, trigger type, and more.
4. 1911 80% Lowers
The 1911 is a classic handgun design that many gun enthusiasts love to build from the ground up. The 1911 80% lower requires more precise machining due to the complexity of the firearm’s design. Building a 1911 from an 80% lower allows for a highly personalized pistol with a rich historical legacy.
Pros and Cons of 80% Lowers
While there are many benefits to using 80% lowers, there are also some drawbacks. Let’s take a closer look at both.
Pros
- Customization: You can create a firearm tailored to your needs and preferences.
- Cost Savings: Building a firearm from an 80% lower can often be more affordable than buying a pre-built gun.
- Privacy: Finished firearms do not have serial numbers, providing privacy for the builder.
- Skill Development: Building a firearm from an 80% lower can be an educational and rewarding experience.
Cons
- Time-Consuming: Building a firearm from an 80% lower takes time and requires skill. It may not be ideal for people looking for an easy and quick way to acquire a firearm.
- Legal Risks: If you do not comply with local, state, and federal laws, you could face legal consequences.
- Initial Investment in Tools: Depending on your existing tool collection, you may need to invest in additional machinery and equipment to complete the lower receiver.
Conclusion
80% lowers offer a unique opportunity for gun enthusiasts to build their own firearms at home, without the need for a federal firearms license in many areas. While they offer a host of advantages, including customization, privacy, and cost savings, there are also legal considerations and challenges involved in completing the build. It’s important to understand the legal landscape in your area and make sure you follow all the proper procedures when building a firearm.
