RL556v3 80% AR15 Lower – Black - polymer 80
Pros & cons
What works
- Weighs 14.6 oz — 0.6 oz lighter than comparable billet lowers
- CNC‑drilled jig cuts milling time by ~20 minutes
- Polymer construction resists corrosion and reduces heat warping
Trade-offs
- No pre‑installed trigger components — requires separate purchase
- Polymer may flex under extreme heat beyond 200 °C, limiting use in sustained automatic fire
- Requires milling of final cutouts; not a plug‑and‑play solution
Video review
Expert review
Specs at a glance
About this product
What is the RL556v3 80% AR15 Lower – Black from ArcForge Arms? It is a polymer lower receiver kit designed for AR‑15 builds, offering a ready‑to‑machine platform that meets 80% compliance regulations.
This black‑finished lower combines a high‑impact 7075‑T6 infused polymer with CNC‑precision tolerances, delivering consistency for both first‑time builders and seasoned customizers. At $85, it balances cost and performance while staying within federal guidelines.
What is the RL556v3 80% AR15 Lower used for?
The lower is used to create a functional AR‑15 lower receiver after milling the final cutouts. It provides the fire control group housing, buffer tube interface, and magazine well needed to complete a rifle. The polymer construction reduces overall weight and eliminates the need for a separate billet machining step, saving roughly 30 minutes of machining time per build.
How does the RL556v3 80% AR15 Lower compare to the .308 80% Lower – Billet?
Compared to the .308 80% Lower – Billet, the RL556v3 is 0.6 oz lighter (14.6 oz vs 15.2 oz) and 20 % faster to finish because polymer requires no deburring after milling.
While the billet lower offers a marginally higher tensile strength, the polymer lower’s durability exceeds 10,000 fire cycles in our testing, which is sufficient for typical civilian use.
What does it weigh and what are the dimensions?
The RL556v3 weighs 14.6 oz (414 g) and measures 9.5 in (241 mm) in length from the rear of the buffer tube to the front of the pistol grip rail.
Its width is 2.5 in (64 mm) and height 2.0 in (51 mm), fitting standard AR‑15 receivers without modification.
Who is this NOT for?
This lower is not for shooters who need a fully machined billet or who require a pre‑stamped design for rapid assembly.
Builders looking for an out‑of‑the‑box ready‑to‑fire rifle will need to purchase additional milling services and a lower parts kit, adding extra cost and time.
What's in the box?
The package includes one RL556v3 polymer lower, a CNC‑drilled jig plate, and a printed alignment guide.
All hardware is pre‑marked for the 80% cut, but no pins, springs, or trigger components are included.
Is the RL556v3 80% AR15 Lower worth it at $85?
Yes, at $85 the lower offers a solid value for its weight, durability, and machining simplicity.
When compared to a comparable billet lower at $115, you save $30 while gaining a 0.6 oz weight reduction and a 20‑minute faster build time.
For detailed registration guidance see our Complete FAQ on the 80% Lower Registration Process and for bulk purchasing timelines check ArcForge Arms Bulk Order Lead Times.
Key attributes
| Caliber | 5.56 NATO |
| Weight | 14.6 oz (414 g) |
| Length | 9.5 in (241 mm) |
| Width | 2.5 in (64 mm) |
| Height | 2.0 in (51 mm) |
| Color | Black |
| Condition | New |
Materials
- polymer
Frequently asked questions
- Is it compatible with a Mil-Spec buffer tube?
- Yes, the RL556v3 lower accepts standard Mil-Spec 14.5‑mm buffer tubes. The external dimensions match the 1.6‑inch receiver extension, allowing direct installation without machining.
- Does it fit a standard AR‑15 pistol grip?
- It fits any AR‑15 compatible pistol grip measuring up to 2.0 in (51 mm) in width. The grip slot is CNC‑tapped to a tolerance of ±0.02 mm for a secure fit.
- How long does shipping take?
- Orders ship via UPS Ground and typically arrive in 3–5 business days within the contiguous United States. Expedited 2‑day shipping is available at checkout for an additional $12.
- Can I return it if it doesn't fit?
- Under our Component Return Policy you have 30 days to return the lower if it is unused and in original packaging. A restocking fee of 15 % applies to returns.
- Does this work with the standard AR‑15 lower parts kit?
- The lower works with any complete AR‑15 lower parts kit, including the trigger, bolt catch, and safety selector. It aligns with the industry‑standard dimensions for all 5.56 NATO components.