The AR-15 platform has revolutionized rifle ownership and customization, and one unique aspect of this movement is the concept of the 80% lower receiver. This component has gained popularity among gun enthusiasts and hobbyists looking for greater control over their firearms. However, there are crucial considerations to keep in mind when it comes to 80% lowers. This article outlines ten important things you should understand about them before diving into a project.
1. What is an 80% Lower Receiver?
An 80% lower receiver is an unfinished lower receiver that requires additional machining to become a fully functional part of an AR-15. Because it is not fully completed, it does not qualify as a firearm under federal law. This makes it legal to purchase without a background check or FFL (Federal Firearms License) transfer in most jurisdictions.
Benefits:
- Privacy: Maintains privacy in firearm ownership.
- Customization: Allows for personalization based on individual preferences.
2. Legal Considerations
Understanding the legal framework around 80% lowers is paramount. While they are legal to buy, sell, and possess in many states, regulations can vary significantly:
- Federal Laws: The ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives) has specific definitions for what constitutes a firearm.
- State and Local Laws: Some states have restrictions on 80% lowers or require them to be serialized. Always check your local laws before purchasing or assembling an 80% lower.
Compatibility with Aftermarket Parts
When upgrading 80% lowers Glock 19 slide, compatibility with aftermarket parts is vitally important.
Compatibility Factors
- Barrel: Ensure your chosen slide can accommodate your preferred aftermarket barrel, particularly if you intend to use custom lengths or ported options.
- Sights and Optics: If you plan to use aftermarket sights or optics, verify that the slide’s cutout patterns match your intended components.
Action Step:
Research the regulations in your state and locality to ensure compliance and avoid legal repercussions.
3. Completing an 80% Lower Requires Tools
Transforming an 80% lower into a functional part requires specific tools and equipment. While some enthusiasts may attempt to use hand tools, investing in the right machinery will enhance accuracy and reduce labor:
- Router: A router is often used to mill out the necessary areas for the trigger pocket and other features.
- Drill Press: Provides precise horizontal and vertical drilling capabilities for the necessary holes.
- Jig Kit: A jig kit matches the specifications of your 80% lower and assists in guiding cuts and drilling.
Action Step:
Ensure that you have access to the appropriate tools and skill level necessary for working with an 80% lower.
4. The Importance of a Quality Jig
A jig is an essential investment when working with 80% lowers. It ensures that your cuts and holes are as precise as possible, leading to a better finished product. High-quality jigs are adjustable and durable, making them suitable for multiple projects.
- Types of Jigs: There are one-piece and two-piece jigs. One-piece jigs are easier to set up, while two-piece jigs offer added versatility for different types of lowers.
Action Step:
Choose a reputable jig that fits your 80% lower for an efficient and accurate build process.
5. The Machining Process is Crucial
Completing an 80% lower involves specific machining processes, including drilling, routing, and possibly finishing. The machining is critical for the function of your future AR-15:
- Tolerance and Accuracy: The areas that require machining must be accurate to ensure that components like the trigger and hammer fit correctly. Improper machining can lead to malfunctions or unsafe conditions.
Action Step:
Take your time and work slowly during the machining process. Use calipers to check measurements and ensure accuracy.
6. Understanding the Assembly
Once the lower receiver is completed, the assembly process begins. Keeping your parts well-organized and understanding the different components is essential:
- Lower Parts Kit (LPK): This includes essential components like the trigger, hammer, and safety selector. Ensure compatibility with your 80% lower.
- Buffer System: Understanding how the buffer tube, buffer spring, and buffer interact with your lower is crucial for proper functioning.
Action Step:
Familiarize yourself with all components of the AR-15 lower, and ensure that you have the necessary parts before starting assembly.
7. Serial Numbers and Compliance
While 80% lowers don’t need to be serialized under federal law, some states require them to be marked upon completion. Additionally, if you ever plan to sell your completed firearm, you may need to serialize it.
Action Step:
Determine if you will need to serialize your completed lower based on your state laws, and have the necessary equipment ready if required.
8. Safety First!
Working with an 80% lower and firearms requires a strong emphasis on safety. This includes not only the machining process but also assembly and operation:
- Protective Gear: Always wear safety goggles and hearing protection when using power tools.
- Safe Work Environment: Ensure you have a clean workspace free of distractions and clutter.
Action Step:
Establish safety protocols before beginning any work on your 80% lower.
9. The Learning Curve
Completing an 80% lower receiver can be a rewarding experience, but it’s important to understand that there is a learning curve involved. Many first-time builders may encounter challenges during the machining and assembly processes:
- Practice: If possible, practice on scrap materials to improve your skills before working on your actual 80% lower.
- Research: Leverage online forums, instructional videos, and guides to better understand the techniques and best practices.
Action Step:
Allocate time to learn and be prepared for mistakes along the way. Building a firearm is a skill that develops with practice.
10. Joining a Community
Finally, joining a community of like-minded enthusiasts can be invaluable. Engaging with other builders can provide insight, support, and answer questions you may have:
- Online Forums and Groups: Participate in online communities, social media groups, or local clubs that focus on firearm building.
- Workshops and Classes: Consider attending workshops to learn from experienced builders.
Action Step:
Seek out groups or forums related to 80% builds for camaraderie and shared knowledge.
Conclusion
Embarking on the journey of completing an 80% lower receiver offers the opportunity for personalized firearm ownership and a deeper understanding of the mechanics of your AR-15. By understanding the essential aspects—legal considerations, tooling requirements, machining processes, safety, and community involvement—you’ll be better equipped to navigate the challenges and triumphs of your build. Enjoy this rewarding endeavor and the sense of achievement that comes with crafting your firearm!