Building a firearm from an 80 percent lower receiver offers enthusiasts a rewarding DIY project while allowing for a high degree of customization. An 80 percent lower is an unregistered firearm component that requires some machining to complete. However, with various options on the market, choosing the right 80 percent lower for your build plan is crucial. This article will guide you through several considerations to help you make an informed decision.
Understanding the 80 Percent Lower
An 80 percent lower receiver is not fully manufactured, meaning it doesn’t meet the criteria of a firearm under federal law. This allows individuals to build their own guns legally without needing to register them. However, because the lower receiver is the part considered the firearm, it must be finished correctly for the gun to function properly.
Legal Considerations
Before selecting 80% lowers, familiarize yourself with local and federal laws. Some states have specific regulations governing the sale and construction of unregistered firearms. Understanding the legal landscape ensures you remain compliant throughout your build process.
Material Choices
The material of your 80 percent lower can significantly impact the weight, durability, and overall performance of your firearm. Common materials include:
Aluminum
- 7075-T6 Aluminum: Known for its high strength-to-weight ratio, this alloy is commonly used in aerospace applications, making it an excellent choice for a durable lower.
- 6061-T6 Aluminum: While slightly less durable than 7075, this is a more common option and still provides good strength for most builds.
Polymer
Polymer lowers are lightweight and often more affordable than aluminum counterparts. However, they may not be as rugged under extreme conditions. If you opt for a polymer lower, ensure it is made of high-quality materials that can withstand the stresses of firing.
Compatibility with Upper Receivers
Ensuring that your 80 percent lower is compatible with your upper receiver is crucial. Most lowers are designed to fit standard AR-15 upper receivers, but some variations may exist. Keep these factors in mind:
Mil-Spec vs. Commercial
- Mil-Spec Lower Receivers: Designed to precise military specifications, mil-spec lowers offer better compatibility with a wider range of components.
- Commercial Lower Receivers: These may vary slightly in dimensions and fit but can still work adequately in many builds.
Always check compatibility with your specific upper before making a purchase.
Design and Features
Different 80 percent lowers come with varying designs and features. When selecting one, consider the following:
Accessories and Customization
Some lowers may come with additional features, such as:
- Integrated Trigger Guards: Helps streamline the appearance and function of the firearm.
- Ambidextrous Controls: Great for left-handed shooters or those who want flexibility.
Choose a design that complements your style and meets your specific requirements.
Engraving and Aesthetic Appeal
For many builders, aesthetics matter just as much as function. Some lowers feature aesthetic engravings, flared mag wells, or custom finishes. If appearance is important to you, look for models that align with your design preferences.
Machining and Assembly Ease
An essential consideration when choosing an 80 percent lower is how easy it is to complete the machining process. Look for these features:
Pre-Drilled or Marked Locations
Some lowers come with pre-drilled holes or marked locations for essential components, making the machining process easier. This can save a lot of time and reduce the potential for mistakes.
Included Jigs and Tools
Many manufacturers offer 80 percent lowers as part of a kit that includes a jig for milling out the necessary components. This can be invaluable for first-timers who may not have the necessary tools for precise work.
Quality Control and Manufacturer Reputation
When selecting an 80 percent lower, consider the manufacturer’s reputation. Research customer reviews and shop around to find products known for quality control. A reputable manufacturer will usually provide better materials, more precise machining tolerances, and reliable customer support.
Budget Considerations
Finally, factor in your budget. Prices for 80 percent lowers can vary widely based on material, features, and brand reputation. While a lower-priced option might seem attractive, investing in a quality product can enhance the overall reliability and performance of your build.
Finding a Balance
Determine how much you’re willing to spend and prioritize features that are most important to your build. Always remember that quality can often outweigh price when it comes to tooling and materials.
Conclusion
Choosing the right 80 percent lower for your build plan requires careful consideration of material, compatibility, features, and manufacturer reputation. By understanding the intricacies of what makes a good lower receiver, you can embark on your assembly project with confidence. With the right 80 percent lower, your DIY firearm build can be both rewarding and successful, unlocking new levels of customization and satisfaction.