The Comprehensive Guide to 80 Percent Lower Receivers

The term 80 percent lower has become increasingly popular among firearms enthusiasts, DIY gunsmiths, and Second Amendment advocates. At, we understand the appeal and practical benefits of building your own firearm, and we’re here to provide you with a detailed guide on everything you need to know about 80 percent lower receivers.

What is an 80 Percent Lower?

An 80 percent lower receiver is a partially completed firearm receiver that requires additional machining to be fully functional. Unlike a fully completed lower receiver, which is classified as a firearm under federal law, an 80 percent lower is not considered a firearm until it has been completed by the owner. This means it can be purchased without a background check or registration.

Why Choose an 80 Percent Lower?

  1. Legal Considerations: One of the main advantages of choosing an 80 percent lower is the ability to build a firearm without the need for a background check. Since 80 percent lowers are not considered firearms by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), they can be purchased and owned by anyone who is legally allowed to own a firearm.
  2. Customization: Building a firearm from an 80 percent lower allows for a high degree of customization. Enthusiasts can select every component, from the trigger assembly to the barrel, ensuring that the final product meets their exact specifications and preferences.
  3. Skill Development: Working on an 80 percent lower provides a hands-on opportunity to learn about firearms and gunsmithing. It’s a rewarding experience that can enhance your understanding of firearm mechanics and maintenance.

The Process of Completing an 80 Percent Lower

Completing an 80 percent lower requires some tools and a bit of know-how, but with the right guidance and patience, it’s a project that can be tackled by most DIY enthusiasts.

Tools Required

  1. Jig Kit: A jig is essential for completing an 80 percent lower. It holds the receiver in place and guides your cutting tools to ensure precise machining.
  2. Drill Press or Milling Machine: To complete an 80 percent lower, you’ll need to drill holes and mill out specific areas. A drill press can suffice for basic tasks, but a milling machine offers greater precision.
  3. End Mills and Drill Bits: These are necessary for cutting and shaping the lower receiver.
  4. Safety Equipment: Always use safety goggles, gloves, and other protective gear to ensure a safe working environment.

Steps to Completion

  1. Setup: Secure the 80 percent lower in the jig, ensuring it’s properly aligned and clamped down.
  2. Drilling: Follow the jig’s guide to drill the required holes for the trigger and hammer pins, selector switch, and other necessary components.
  3. Milling: Using the appropriate end mill, machine the fire control cavity to the correct dimensions.
  4. Finishing Touches: Deburr any rough edges, clean the lower receiver, and inspect your work to ensure all dimensions are correct and the receiver is smooth.

Legal Considerations

While an 80 percent lower is not considered a firearm under federal law, it’s important to be aware of state and local regulations. Some states have specific laws regarding the manufacture and ownership of homemade firearms. Always check your local laws before starting your project to ensure compliance.

At, we provide detailed guides and support to help you navigate these regulations and ensure your build is legal and safe.

Common Questions About 80 Percent Lowers

Is it legal to complete an 80 percent lower?

Yes, it is legal to complete an 80 percent lower for personal use, as long as you are not prohibited from owning a firearm and you comply with all federal, state, and local laws.

Do I need a serial number on my completed 80 percent lower?

Federal law does not require a serial number on a completed 80 percent lower if it is for personal use. However, some states have laws that may require serialization, especially if you plan to transfer or sell the firearm.

Can I sell a firearm built from an 80 percent lower?

Selling a firearm built from an 80 percent lower is subject to federal and state regulations. You may need to serialize the firearm and follow the appropriate transfer procedures, including background checks and paperwork. Always consult legal advice if you intend to sell your homemade firearm.

Quality and Precision at

At, we pride ourselves on providing high-quality 80 percent lower receivers and the tools you need to complete your build. Our products are crafted with precision and durability in mind, ensuring that your finished firearm will be reliable and accurate.

We also offer a range of resources, including detailed guides, instructional videos, and customer support, to assist you at every step of your project. Whether you’re a seasoned gunsmith or a novice enthusiast, is your trusted partner in building your own firearm.

Read more Motorcycle Touring: How to Prepare for an Epic Adventure


Building a firearm from an 80 percent lower is a rewarding and empowering experience. It offers the freedom to create a custom firearm tailored to your preferences and needs. With the right tools, knowledge, and support from, you can successfully complete your project and enjoy the satisfaction of building your own firearm.

Remember, safety and legal compliance are paramount. Always adhere to safety protocols and verify your local laws before beginning your build. With careful planning and execution, your 80 percent lower project can be a fulfilling and educational endeavor.

Explore our selection of 80 percent lowers and start your journey towards building a custom firearm with today!

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button