Polymer80 RL556V3 – RHINO 80% AR15 Lower Receiver with Jig
Pros & cons
What works
- Forged 7075-T6 aluminum construction - matches military specification hardness
- Includes $200+ worth of premium tooling - three carbide end mills and precision drill bits
- Easy Jig Gen 3 system reduces setup time to under 15 minutes compared to older jigs
- 8.2 ounce unfinished weight - lighter than many billet alternatives by 1.5-2 ounces
Trade-offs
- Requires drill press or router - adds $150-400 tooling cost if not already owned
- No step-by-step video included - beginners must seek external resources for visual guidance
- Jig alignment critical - 0.010 inches misalignment can ruin lower receiver permanently
- 80% completion status - not legal for use until properly machined and serialized if required by state law
Video review
Expert review
Specs at a glance
About this product
The Polymer80 RL556V3 RHINO 80% AR15 Lower Receiver with Jig is a forged 7075-T6 aluminum 80% lower receiver kit that includes the Easy Jig Gen 3 system and all necessary tooling for completion. This is the most comprehensive DIY builder solution for experienced firearms enthusiasts seeking military-grade components without serialization requirements. The system bridges the gap between raw forging and functional lower receiver with professional-grade precision.
What is the Polymer80 RL556V3 RHINO 80% AR15 Lower Receiver with Jig used for?
This kit is designed for completing an 80% lower receiver into a functional AR-15 lower using the included Easy Jig Gen 3 system and tooling. You'll need a drill press or router, basic machining skills, and approximately 2-3 hours of focused work time to achieve proper fire control group pocket dimensions. The finished lower accepts all standard AR-15 parts kits and operates with mil-spec upper receivers.
How does the Polymer80 RL556V3 compare to the 80% Lower Fire/Safe Marked – Anodized Black?
The RL556V3 kit includes the complete Easy Jig Gen 3 system and tooling, while the Fire/Safe Marked lower sold separately requires purchasing the jig system separately. The RL556V3 provides better value at $0.0 versus buying components individually, though both share identical 7075-T6 aluminum construction and anodized black finish. For builders needing just the raw lower without tooling, consider our 80% Lower Fire/Safe Marked – Anodized Black.
What does it weigh and what are the dimensions?
The unfinished lower receiver weighs 8.2 ounces with dimensions of 7.5 inches long, 2.1 inches wide, and 1.5 inches tall. The complete kit with jig, tooling, and lower weighs approximately 4.2 pounds. Critical machining areas require removal of 0.125 inches of material from the trigger pocket and 0.250 inches from the safety selector hole.
Who is this NOT for?
This product is not for beginners without machining experience or those lacking access to a drill press or router. The process requires steady hands, understanding of alignment procedures, and tolerance for metalworking debris. If you're uncomfortable with permanent modification of firearm components, consider our complete lower receivers instead.
What's in the box?
The kit includes one 80% forged 7075-T6 aluminum lower receiver, Easy Jig Gen 3 milling jig, three carbide end mills (1/4", 5/16", 3/8"), two drill bits (#3 and #21), alignment pins, and installation hardware. All tooling is premium quality capable of handling aluminum without dulling prematurely. Reference our 80% Lower Receiver Jig Alignment Pin Specifications article for proper setup.
Is the Polymer80 RL556V3 worth it at $0.0?
At $0.0, this kit represents significant value compared to purchasing the jig system and tooling separately, which would cost approximately $200-$300. The forged 7075-T6 aluminum construction ensures durability matching military specifications, though the completion process requires time and skill investment. For builders planning multiple projects, the reusable jig system makes this an economical choice.
Key attributes
| Material | Forged 7075-T6 aluminum |
| Finish | Black anodized |
| Weight | 8.2 oz (unfinished) |
| Dimensions | 7.5 x 2.1 x 1.5 inches |
| Completion Status | 80% lower |
| Jig System | Easy Jig Gen 3 |
| Compatibility | AR-15 platform |
| Included Tooling | 3 end mills, 2 drill bits |
Specifications
| material | Forged 7075-T6 aluminum |
| finish | Black |
| jig_type | Easy Jig Gen 3 |
| compatibility | AR-15 platform |
| completion_status | 80% lower |
| included_tooling | Premium drill bits and end mills |
| intended_use | Custom firearm building |
Best for
- Custom AR-15 rifle building
- Firearm DIY projects
- Personal firearm customization
Materials
- 7075-T6 aluminum
What's in the box
- 80% AR15 lower receiver
- Easy Jig Gen 3
- Premium tooling (drill bits, end mills)
Care
Frequently asked questions
- Is it compatible with standard AR-15 parts kits?
- Yes, the completed lower accepts all mil-spec AR-15 parts kits including triggers, pistol grips, and buffer tubes. The fire control group pocket dimensions match standard specifications within 0.005 inches tolerance. Use any commercial lower parts kit from brands like Anderson Manufacturing or Aero Precision.
- Does the jig work with polymer 80% lowers?
- No, the Easy Jig Gen 3 is specifically designed for aluminum lowers and requires different alignment procedures than polymer jigs. Attempting to use this jig with polymer lowers may result in misalignment and ruined components. For polymer projects, use dedicated polymer jig systems.
- How long does shipping take?
- Standard shipping processing time is 3-5 business days with additional transit time based on carrier. Expedited options available for 1-2 day processing. All shipments require adult signature confirmation and comply with federal shipping regulations for firearm components.
- Can I return it if I mess up the machining?
- No, once machining has begun the product cannot be returned due to ATF regulations regarding altered firearm components. The jig system provides precise guidance but requires proper tool operation. Practice on scrap aluminum first if you're new to machining processes.
- Does this work with ambidextrous safety selectors?
- Yes, the safety selector hole is drilled to standard dimensions accepting both mil-spec and ambidextrous selectors. The pocket requires final reaming to 0.250 inches diameter. Reference our <a href="/blog/arc-firetrigger-ambidextrous-magazine-release-install-tutorial/">ARC Firetrigger Ambidextrous Magazine Release Install Tutorial</a> for installation techniques.