Building your own AR-10 from an 80% lower receiver can be a rewarding experience, offering customization and potential cost savings. However, it's crucial to understand the legal implications and technical aspects involved. This guide delves into the intricacies of AR-10 80% lower receivers, providing a comprehensive overview for both beginners and experienced builders.
Understanding AR-10 80% Lower Receivers
An AR-10 80% lower receiver is an unfinished firearm receiver that lacks the critical components necessary to function as a complete firearm. The term "80%" refers to the percentage of machining or milling that's already complete. The remaining 20% requires finishing via jigging and machining to become a functional lower receiver. This unfinished state allows it to bypass certain regulations in some jurisdictions. Crucially, this does not exempt it from all firearm laws. Always check your local, state, and federal regulations before purchasing or working with an 80% lower. Failure to comply with applicable laws can result in serious legal consequences.
Key Differences from a Complete Lower: An 80% lower receiver lacks the fire control group pocket, trigger housing, and often the rear takedown pin holes. These features must be added during the completion process. This typically requires specialized tools and some degree of mechanical aptitude.
Materials: AR-10 80% lowers are commonly made from 7075-T6 aluminum, a strong and durable material suitable for the stresses of firing a .308 caliber round (or similar). Steel lowers are less common but offer increased durability.
The Process of Completing an AR-10 80% Lower
Completing an AR-10 80% lower is not a simple task and requires the right tools and knowledge. Improper completion can result in a dangerous and unreliable firearm.
Necessary Tools and Equipment:
- 80% lower receiver jig: This jig accurately guides the milling process, ensuring the necessary features are correctly located and dimensioned. Choosing the right jig for your specific lower is crucial.
- Milling machine or router: The jig will be used in conjunction with a milling machine or a powerful router with appropriate bits. A milling machine is preferred for accuracy and consistency.
- Appropriate bits: The correct size and type of end mills or router bits are essential for clean and precise cuts. Using the wrong bits can ruin the lower receiver.
- Safety glasses and hearing protection: Always prioritize safety when working with power tools.
- Measuring tools: Calipers and other measuring instruments are needed to verify dimensions throughout the process.
Steps to Completion (General Overview):
- Secure the 80% lower in the jig: Follow the manufacturer’s instructions carefully.
- Mill out the required features: This includes the fire control group pocket, trigger housing, and rear takedown pin holes. Take your time and work slowly to ensure accuracy.
- Deburr and clean: Remove any burrs or sharp edges to improve functionality and safety.
- Final inspection: Carefully check all dimensions and ensure the receiver is free of defects.
Caution: This is a simplified overview. The exact process varies depending on the specific 80% lower receiver and the jig used. Always consult the manufacturer's instructions and watch instructional videos before starting.
Legal Considerations for AR-10 80% Lowers
The legality of 80% lowers varies significantly by location. Some jurisdictions have strict regulations or outright bans on their possession or manufacture. It is your responsibility to understand and comply with all applicable federal, state, and local laws. Possessing or manufacturing a firearm in violation of these laws can lead to severe penalties.
- Federal Laws: Federal laws generally do not regulate 80% lowers directly unless they are subsequently assembled into a complete firearm that fails to meet registration requirements.
- State Laws: State laws vary dramatically. Some states have enacted stricter regulations, including requiring registration or prohibiting the possession of 80% lowers altogether.
- Local Ordinances: Local municipalities may also have ordinances impacting the ownership or use of 80% lowers.
Conclusion: Responsible Ownership and Building
Building an AR-10 from an 80% lower receiver can be a rewarding endeavor, but it requires careful planning, precise execution, and strict adherence to all applicable laws. Always prioritize safety and understand the potential legal ramifications before undertaking this project. Research your local regulations thoroughly and consult with qualified professionals if you have any doubts or questions. Remember, responsible gun ownership is paramount.