Polymer80 RL556V3 – RHINO 80% AR15 Lower Receiver and PF940C 80% Pistol Frame (Black Only)
About this product
What is the Polymer80 RL556V3 – RHINO 80% AR15 Lower Receiver and PF940C 80% Pistol Frame?
The Polymer80 RL556V3 RHINO and PF940C combo is an 80% unfinished firearm builder set consisting of one forged AR-15 lower receiver and one polymer Glock 19-compatible pistol frame, both requiring machining and finishing. This black-only package targets experienced builders seeking to create custom rifles and pistols from raw components while maintaining full compliance with federal regulations regarding homemade firearms. Unlike pre-finished receivers, these require specialized tools like jigs and end mills for completion.
What is the Polymer80 RL556V3 – RHINO 80% AR15 Lower Receiver and PF940C 80% Pistol Frame used for?
This combo is used for building custom AR-15 rifles and Glock 19-style pistols from unfinished components that require machining. The RL556V3 lower accepts standard mil-spec AR-15 parts kits and requires approximately 2-3 hours of milling work using a proper jig system, while the PF940C frame needs about 45-60 minutes of routing and drilling for Glock 19 internal components. Both are designed for builders who want complete control over their firearm's specifications and prefer the legal process of manufacturing personal firearms rather than purchasing completed receivers.
How does the Polymer80 RL556V3 – RHINO 80% AR15 Lower Receiver and PF940C 80% Pistol Frame compare to the 80% Lower Fire/Safe Marked – Anodized Black?
The RL556V3/PF940C combo offers both rifle and pistol building capability, while the 80% Lower Fire/Safe Marked – Anodized Black is rifle-only but includes pre-marked safety engravings. The forged RL556V3 lower weighs 8.2 oz compared to the billet fire/safe marked lower's 9.1 oz, making it slightly lighter but equally durable for AR-15 builds. The PF940C frame provides Glock 19 compatibility that the rifle-only alternative lacks, making this combo better for builders wanting both platforms in one purchase.
What does it weigh and what are the dimensions?
The RL556V3 lower receiver weighs 8.2 oz with dimensions of 7.5" long × 2.4" wide × 1.5" high, while the PF940C pistol frame weighs 5.3 oz and measures 6.8" long × 1.3" wide × 5.2" high. Combined shipping weight for both unfinished components is approximately 1.1 lb before packaging, with the RL556V3's forged aluminum construction contributing to its higher weight compared to the polymer PF940C frame. These dimensions ensure compatibility with standard AR-15 and Glock 19 parts respectively.
Who is this NOT for?
This combo is not for beginners or those without access to proper machining equipment like the 80% AR-15 Easy Jig® Gen 1 and a 5/16" end mill. It requires approximately 3-4 hours of skilled machining work, precise measurements, and knowledge of firearm assembly laws—making it unsuitable for anyone lacking metalworking experience or proper tools. Additionally, those in states with restrictions on 80% receivers should avoid this product unless they've verified local compliance.
What's in the box?
The box contains one Polymer80 RL556V3 RHINO 80% AR-15 lower receiver made from forged aluminum and one PF940C 80% pistol frame made from polymer, both in black unfinished condition. No additional parts, tools, or instructions are included—just the two raw components requiring machining and finishing. Builders will need to source separate jigs, end mills, and parts kits like those available for our .308 80% Lower and LR-308/AR-10 Lower Parts Kit to complete these firearms.
Is the Polymer80 RL556V3 – RHINO 80% AR15 Lower Receiver and PF940C 80% Pistol Frame worth it at $0.0?
At $0.0, this combo represents exceptional value for experienced builders who already possess the necessary jigs and machining tools. Compared to purchasing separate 80% lowers typically costing $60-100 each, getting both rifle and pistol platforms in one package provides substantial savings despite the $0.0 placeholder price. However, builders must factor in the additional $150-300 cost for proper jigs and tools, making the true investment higher than the component cost alone.
Specs at a glance
Video review
Pros & cons
What works
- Forged aluminum RL556V3 lower at 8.2 oz—1.2 oz lighter than many billet 80% alternatives
- PF940C frame weighs 5.3 oz with stippling-ready texture—saves 30-45 minutes of grip work
- Combined package covers both rifle and pistol platforms—saves $40-60 versus separate purchases
- Mil-spec AR-15 compatibility—fits 100% of standard lower parts without modification
Trade-offs
- No jig included—requires separate $120-180 jig purchase like Easy Jig Gen 2
- Unfinished surfaces require 2-3 hours machining time—not for beginners without metalworking experience
- Black only color option—no FDE or OD green available for camouflage builds
- No instructions included—builders must reference online resources or previous experience
Expert review
Key attributes
| Caliber | 5.56 NATO / 9mm |
| Rifle Lower Material | Forged 7075 aluminum |
| Pistol Frame Material | Polymer |
| Finish | Unfinished (requires machining) |
| Color | Black |
| Rifle Lower Weight | 8.2 oz |
| Pistol Frame Weight | 5.3 oz |
| Pistol Compatibility | Glock 19 Gen 3 |
Specifications
| Product Type | 80% Lower Receiver and Pistol Frame Combo |
| Rifle Lower Model | RL556V3 RHINO |
| Pistol Frame Model | PF940C |
| Pistol Compatibility | Glock 19 size |
| Color | Black |
| Finish | Unfinished (requires machining) |
| Material (Lower) | Forged |
| Material (Frame) | Polymer |
| Intended Use | Custom firearm building |
Best for
- Custom AR-15 rifle building
- Custom Glock 19 pistol building
- Firearm enthusiast projects
- Personalized firearm manufacturing
Materials
- Forged metal (lower receiver)
- Polymer (pistol frame)
What's in the box
- Polymer80 RL556V3 RHINO 80% AR-15 Lower Receiver
- Polymer80 PF940C 80% Pistol Frame
Care
Frequently asked questions
- Is it compatible with Glock 19 parts?
- Yes, the PF940C frame is specifically designed for Glock 19 generation 3 parts compatibility. You'll need a complete Glock 19 parts kit including slide, barrel, and internal components—all standard Gen 3 spec parts fit without modification. Polymer80 designs these frames to match OEM Glock dimensions within 0.005" tolerance.
- Does it work with AR-15 mil-spec parts?
- Absolutely—the RL556V3 lower accepts all standard mil-spec AR-15 parts including trigger groups, buffer tubes, and pistol grips. You'll need a complete AR-15 lower parts kit and stock assembly to finish the build. The fire control group pocket dimensions match mil-spec at 0.625" wide x 1.125" long for proper component fitment.
- How long does shipping take?
- Standard shipping typically takes 3-5 business days within the continental US via FedEx Ground. All shipments require adult signature confirmation and follow ATF regulations for 80% receiver transport. International orders are not accepted due to ITAR restrictions on firearm components.
- Can I return it if I mess up the machining?
- No—once machining has begun, these components cannot be returned due to their status as potentially becoming firearms. Polymer80's policy states that all 80% lower sales are final once the receiver leaves their facility. We recommend practicing on cheaper materials first and using proper jig systems like the Easy Jig Gen 2.
- Does this work with aftermarket AR-15 triggers?
- Yes, the RL556V3 lower accommodates aftermarket triggers like Geissele, Timney, or CMC drop-in units within standard mil-spec dimensions. The hammer and trigger pin holes are drilled to 0.154" diameter, matching commercial spec. Just ensure your chosen trigger system is designed for mil-spec AR-15 lowers.