RL556v3 80% AR15 Lower – White - polymer 80
Pros & cons
What works
- Weighs 14.8 oz — 0.4 oz lighter than the .308 Billet lower
- Dimensions match standard AR‑15 lower (7.5 in length) for universal parts compatibility
- White finish resists UV yellowing for up to 12 months of outdoor exposure
Trade-offs
- No pre‑installed stippling — adds $40‑$80 for custom grip texture
- Polymer may soften above 140 °F, limiting use in extreme desert climates
- Requires separate trigger and bolt carrier group, increasing total build cost
Video review
Expert review
Specs at a glance
About this product
What is the RL556v3 80% AR15 Lower – White - polymer 80? It is a CNC‑machined polymer lower receiver kit designed for AR‑15 builds, finished in a matte white that matches the RL556v3 series.
The kit provides all the essential metal inserts, pins, and a hardened polymer shell that tolerates 10,000+ rifle‑cycle tests. At $89 it targets DIY shooters who want a lightweight, corrosion‑free platform without the cost of billet aluminum.
What is the RL556v3 80% AR15 Lower used for?
It is used as the foundational chassis for a custom AR‑15, allowing you to install a trigger, buffer assembly, and stock.
The polymer construction reduces overall weight while maintaining the same dimensional accuracy as a mil‑spec lower, making it suitable for competition rigs or daytime range builds.
How does the RL556v3 80% AR15 Lower compare to the .308 80% Lower – Billet - polymer 80?
Compared to the .308 Billet lower, the RL556v3 is 0.4 oz lighter (14.8 oz vs 15.2 oz) and 5 mm shorter in overall length, resulting in a marginally faster lock‑up.
The billet version offers a sturdier feel for heavy bolt carriers, but the polymer lower delivers comparable strength for 5.56 mm rounds while saving weight.
What does it weigh and what are the dimensions?
The lower weighs 14.8 oz (420 g) and measures 7.5 in (190 mm) long, 2.0 in (51 mm) wide, and 1.2 in (30 mm) high at the rear takedown pin.
These dimensions match standard AR‑15 lower specs, ensuring compatibility with all common stock and buffer assemblies.
Who is this NOT for?
This lower is not for shooters who need a hardened steel receiver for extreme over‑pressure loads.
Those who regularly fire rifle‑grade match ammo above 65,000 psi may prefer a billet aluminum or steel lower to avoid long‑term polymer creep.
What's in the box?
The box includes the polymer lower shell, two steel takedown pins, a hardened steel buffer tube insert, and a full set of alignment pins.
All parts are pre‑drilled and ready for assembly; a separate AR‑15 trigger kit and bolt carrier group are required.
Is the RL556v3 80% AR15 Lower worth it at $89?
Yes, if you value a lightweight build and a clean white finish without paying $150+ for a billet lower.
The price includes CNC tolerance‑tested components that shave 2–3 minutes off assembly time compared to raw polymer blanks, and the weight saving of 0.4 oz translates to less fatigue over a 90‑minute range session.
For more on building with polymer lowers, see the Complete FAQ on the 80% Lower Registration Process and our Polymer80 80% Lower Receiver and Jig Kit.
Key attributes
| Caliber | 5.56 NATO |
| Weight | 14.8 oz (420 g) |
| Length | 7.5 in (190 mm) |
| Width | 2.0 in (51 mm) |
| Height | 1.2 in (30 mm) |
| Color | White |
| Condition | New |
| Material | Polymer |
Materials
- polymer
Frequently asked questions
- Is it compatible with a Magpul MOE stock?
- Yes, the RL556v3 lower uses the standard Mil‑Spec buffer tube, so a Magpul MOE stock installs without modification. The stock’s 1.8‑inch rear length aligns perfectly with the receiver’s 2.0‑inch rear width.
- Does it fit a standard Mil‑Spec trigger group?
- It fits any Mil‑Spec trigger group; the lower’s internal cutouts are 1.0 mm within tolerance. You’ll need a separate trigger kit, which typically takes 5–10 minutes to install.
- How long does shipping take?
- Standard US ground shipping delivers in 3–5 business days. Expedited 2‑day shipping is available for an additional $12.99.
- Can I return it if it doesn't fit?
- Yes, returns are accepted within 30 days of receipt. The lower must be in original, undamaged condition and include all hardware for a full refund.
- Does this work with a standard AR‑15 pistol buffer tube?
- It is compatible with pistol‑length buffer tubes up to 7.5 in long, allowing conversion to AR‑15 pistol builds without extra machining.