When starting your AR-15 or AR-10 build, one of the first decisions you’ll face is choosing between an 80% lower receiver and a stripped lower receiver. Both options serve as the foundation for your firearm, but they come with distinct differences in terms of cost, customization, legal considerations, and the overall building process.
In this article, we’ll break down the key differences between 80 percent lowers and stripped lowers to help you decide which is the best choice for your next build.
What Is an 80% Lower Receiver?
An 80% lower receiver is a partially machined lower that requires additional work to become functional. Specifically, it lacks the necessary machining to house the fire control group (trigger, hammer, and safety selector).
Key Characteristics:
- Not Classified as a Firearm: Since it is unfinished, it is not legally considered a firearm under federal law.
- Requires Completion: Builders must machine the fire control cavity and drill the pin holes to make it functional.
- DIY Build Opportunity: Completing an 80% lower allows for a hands-on, customizable building experience.
What Is a Stripped Lower Receiver?
A stripped lower receiver is fully machined and ready to accept components like the trigger group, buffer system, and stock.
Key Characteristics:
- Legally a Firearm: Classified as a firearm under federal law, requiring a background check and FFL transfer for purchase.
- No Machining Required: Ready for assembly out of the box.
- Pre-Specified Design: Comes with pre-drilled holes and a pre-machined fire control cavity.
Comparing 80 Percent Lowers and Stripped Lowers
1. Cost
80% Lower:
- Initial Cost: Typically cheaper than stripped lowers, ranging from $50 to $100 depending on the material and finish.
- Additional Costs: Requires a jig kit ($50–$300) and tools like a drill press or router, which are reusable for future builds.
Stripped Lower:
- Initial Cost: More expensive, typically ranging from $80 to $200 depending on the brand and material.
- No Additional Costs: Ready to assemble with no need for jigs or machining tools.
Winner for Cost:
- Single Build: Stripped lower (no need for extra tools).
- Multiple Builds: 80% lower (jig and tools become cost-effective over time).
2. Legal Considerations
80% Lower:
- No Background Check or FFL: Since it’s not a firearm, you can purchase it without paperwork in most states.
- State Restrictions: Some states (e.g., California, New York) require serialization or prohibit possession of unserialized lowers.
Stripped Lower:
- Background Check Required: Must be purchased through an FFL with a background check.
- Universal Compliance: Legal in all states where AR-15-style firearms are allowed.
Winner for Privacy:
- 80% lower (in states where it’s legal to own).
3. Customization
80% Lower:
- Full Control: You’re starting from a blank slate, allowing for unique engravings, finishes, and design choices.
- Material Options: Available in aluminum and polymer, each suited to different build goals.
Stripped Lower:
- Limited Options: Comes pre-machined and finished, with fewer opportunities for personalization.
- Engraving Options: Some stripped lowers offer customization, but at an additional cost.
Winner for Customization:
- 80% lower (greater freedom to create a truly custom firearm).
4. Skill Building and Hands-On Experience
80% Lower:
- DIY Learning Opportunity: Completing an 80% lower teaches machining skills and provides a deeper understanding of firearm mechanics.
- Time Commitment: Requires more time and effort, especially for first-time builders.
Stripped Lower:
- Quick and Easy Assembly: Ideal for builders who want a functional firearm without investing in machining skills.
- Limited Skill Development: Minimal learning beyond assembly.
Winner for Skill Building:
- 80% lower (hands-on experience and knowledge-building).
5. Build Time
80% Lower:
- Completion Time: The machining process adds several hours to the build.
- Preparation Required: Requires setup of tools, jigs, and workspace.
Stripped Lower:
- Assembly-Ready: Allows you to skip the machining process and focus solely on assembling the firearm.
- Fast Turnaround: A stripped lower can be fully assembled in less than an hour.
Winner for Speed:
- Stripped lower (ready-to-assemble out of the box).
6. Performance and Reliability
Both 80% lowers and stripped lowers can perform equally well if machined and assembled correctly. However, poor machining of an 80 lower can lead to issues like:
- Misaligned holes.
- Uneven fire control cavities.
Tips to Ensure Performance with an 80% Lower:
- Use a high-quality jig kit and tools.
- Follow detailed guides or tutorials.
- Take your time to avoid over-milling or drilling mistakes.
Winner for Ease of Performance:
- Stripped lower (minimal risk of errors).
Who Should Choose an 80% Lower?
An 80% lower is ideal for:
- DIY Enthusiasts: Builders who enjoy hands-on projects and learning new skills.
- Privacy-Minded Individuals: Those who prefer to purchase without an FFL transfer or background check.
- Customizers: Gun owners who want full control over every aspect of their build.
- Multiple Builds: Builders who plan to create multiple firearms and can reuse jigs and tools.
Who Should Choose a Stripped Lower?
A stripped lower is ideal for:
- First-Time Builders: Those looking for an easier, faster build experience.
- Quick Turnaround: Builders who want a functional firearm without additional machining.
- One-Time Projects: People who don’t plan to invest in jigs or tools for future builds.
Final Thoughts
Choosing between an 80% lower receiver and a stripped lower receiver comes down to your goals, preferences, and skill level.
- If you value customization, privacy, and skill-building, an 80 lower is the way to go.
- If you want a fast and straightforward build, a stripped lower is the better choice.
Both options have their merits, and either can form the foundation of a reliable, high-performing AR-15 or AR-10.
Ready to start your build? Check out Thunder Guns for premium 80% lowers, stripped lowers, and all the tools and components you need to create your ideal firearm. Happy building!