Understanding the 80% Lower: A Comprehensive Guide

In recent years, the concept of the “80% lower” has gained significant traction among firearms enthusiasts, hobbyists, and DIY aficionados. An 80% lower, as the name suggests, is a firearm receiver that is only 80% complete, leaving the final 20% of machining and assembly up to the purchaser. This incomplete status allows the product to be sold without the same regulations that govern complete firearms. For those who enjoy the process of building their own guns, an 80% lower represents a unique and rewarding challenge. At, we provide everything you need to embark on this exciting journey.

What is an 80% Lower?

An 80% lower is essentially a partially completed lower receiver for a firearm, typically an AR-15. The lower receiver is the part of the gun that houses the trigger group and magazine well. Because an 80% lower is not finished, it is not considered a firearm by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). This distinction means that it can be purchased and shipped without the need for a background check or serial number. At, we specialize in high-quality 80% lowers that are perfect for your next build.

Why Choose an 80% Lower?

There are several reasons why someone might choose to build their own firearm using an 80% lower. Here are a few key benefits:

  1. Customization: Building your own firearm from an 80% lower allows for a high degree of customization. You can select every component to fit your preferences and needs.
  2. Cost Savings: Purchasing an 80% lower and completing the build yourself can often be more cost-effective than buying a fully assembled firearm.
  3. Educational Experience: For those who enjoy hands-on projects, completing an 80% lower is an excellent way to learn more about the mechanics of firearms.
  4. Privacy: Since 80% lowers are not considered firearms, they do not require a serial number, allowing for greater privacy.

At, we cater to enthusiasts who value these benefits and are looking for high-quality parts to complete their custom builds.

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The Process of Completing an 80% Lower

Completing an 80% lower requires some basic tools and skills. Here is a step-by-step overview of the process:

  1. Select Your 80% Lower: The first step is to choose a quality 80% lower receiver. At, we offer a variety of options to suit different needs and preferences.
  2. Gather Tools and Jigs: You will need a set of tools, including a drill press or milling machine, drill bits, and an 80% lower jig to guide your cuts. The jig is essential for ensuring precise cuts and proper alignment.
  3. Drill and Mill: Follow the instructions provided with your jig to drill and mill the necessary holes and cavities in the lower receiver. This step requires patience and precision.
  4. Finish and Assemble: Once the machining is complete, you can finish the receiver by sanding and painting it, if desired. Then, assemble the remaining parts to complete your firearm.

Legal Considerations

It’s important to be aware of the legal considerations surrounding 80% lowers. While they can be purchased and shipped without a background check, completing an 80% lower does come with responsibilities. Here are a few key points to keep in mind:

  • Federal Laws: Under federal law, it is legal to build a firearm for personal use without a serial number, as long as you are not prohibited from owning firearms. However, selling a homemade firearm requires a serial number and adherence to federal regulations.
  • State Laws: Some states have additional regulations regarding 80% lowers and homemade firearms. It’s crucial to research and comply with your state’s laws before starting your build.

At, we encourage all customers to understand and follow the legal requirements in their area.

Choosing the Right 80% Lower

Selecting the right 80% lower is crucial for a successful build. Here are some factors to consider:

  • Material: 80% lowers are typically made from aluminum or polymer. Aluminum lowers are durable and provide a traditional feel, while polymer lowers are lightweight and resistant to corrosion.
  • Design: Consider the design and features of the lower receiver, such as the type of trigger guard and magazine well. These features can affect the functionality and comfort of your finished firearm.
  • Compatibility: Ensure that the 80% lower you choose is compatible with the other components you plan to use in your build.

At, we offer a range of 80% lowers to meet different needs and preferences, ensuring you can find the perfect fit for your project.

Tips for a Successful Build

Building a firearm from an 80% lower can be a rewarding experience, but it requires careful planning and attention to detail. Here are some tips to help you succeed:

  • Take Your Time: Rushing through the machining process can lead to mistakes. Take your time to ensure precision and accuracy.
  • Follow Instructions: Use the instructions provided with your jig and tools. These guides are designed to help you achieve the best results.
  • Seek Advice: If you are new to building firearms, seek advice from experienced builders or online communities. At, we are also happy to provide guidance and support.


An 80% lower offers a unique opportunity for firearms enthusiasts to create their own custom builds while enjoying the educational and practical benefits of a hands-on project. At, we are committed to providing high-quality 80% lowers and the resources you need to complete your build successfully. Whether you are looking to save money, customize your firearm, or simply enjoy the process, an 80% lower is a great choice. Remember to always follow legal requirements and take your time to ensure a safe and functional firearm. Happy building!

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