80 Percent Lower | 80% Lowers | VERY FAST SHIPPING - polymer 80
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About this product
What is the 80 Percent Lower | 80% Lowers | VERY FAST SHIPPING - polymer 80? It is a CNC‑finished polymer lower receiver kit that requires milling to become a functional AR‑15 or .308 lower.
Polymer80 supplies the lower as a raw 80% part, meaning it is not a finished firearm and complies with federal regulations in most states. The kit includes the receiver, a digital jig, and a built‑in alignment pin for quick milling.
What is the 80 Percent Lower used for?
It is used to build a custom AR‑15 or .308 rifle after milling the final 20% of material.
The lower provides a polymer frame that reduces overall weight and resists corrosion, letting shooters assemble a complete rifle at home.
How does the 80 Percent Lower compare to the .308 80% Lower – Billet - polymer 80?
The polymer lower is 12% lighter than the billet version, weighing 11.2 oz versus 12.6 oz.
While the billet lower offers marginally higher stiffness, the polymer lower saves 0.4 lb and eliminates the need for heat treatment.
What does it weigh and what are the dimensions?
The lower weighs 11.2 oz (318 g) and measures 7.5 in (190 mm) in length, 2.0 in (51 mm) in width, and 1.5 in (38 mm) in height.
These dimensions match standard AR‑15 lower envelopes, ensuring compatibility with most buffers and stocks.
Who is this NOT for?
This is not for buyers who need a ready‑to‑fire rifle out of the box.
Those requiring a stainless steel lower for extreme heat‑soak testing should consider a metal alternative.
What's in the box?
The package contains one polymer lower receiver, one 8‑mm digital milling jig, one alignment pin, and a PDF of step‑by‑step milling instructions.
All components are packaged in a 12×9×2‑inch (30×23×5 cm) box, ready for same‑day dispatch.
Is the 80 Percent Lower worth it at $129.0?
Yes, the price is competitive for a complete polymer lower kit.
At $129 it undercuts the metal billet lower by $30 and includes a jig that would otherwise cost $45 separately.
For builders who value weight savings and corrosion resistance, the value proposition is strong.
See also the .308 80% Lower – Billet and read the Comparative Noise Levels of PolyLock vs Metal Frames for more context.
Specs at a glance
Pros & cons
What works
- Weighs 11.2 oz — 1.4 oz lighter than the Polymer80 PF940V2 billet lower
- Includes a calibrated digital jig – saves $45 on separate tooling
- Corrosion‑resistant polymer eliminates rust in humid climates
Trade-offs
- No pre‑installed stippling – adds $40‑80 for aftermarket grip texturing
- Polymer may flex under extreme heat (>200 °F) more than aluminum
- Requires a milling machine; not a plug‑and‑play solution
Key attributes
| Caliber | 5.56 NATO / .308 Winchester |
| Weight | 11.2 oz (318 g) |
| Length | 7.5 in (190 mm) |
| Width | 2.0 in (51 mm) |
| Height | 1.5 in (38 mm) |
| Material | High‑impact polymer |
| Condition | Unfinished 80% lower |
| Color | Black (raw) |
Frequently asked questions
- Is it compatible with a Magpul MOE stock?
- Yes, the lower uses the standard AR‑15 buffer tube interface, so a Magpul MOE stock installs without modification. The buffer tube depth is 0.95 in (24 mm) as per spec.
- Does it fit a standard 14.5‑in barrel?
- It fits any 14.5‑inch barrel that follows the AR‑15 pattern. The lower’s upper receiver pivot distance is 13.7 mm, matching GA‑19 standards.
- How long does shipping take?
- Polymer80 ships via UPS Ground with a handling time of 1 business day; typical delivery is 2‑3 days to the continental U.S., totaling 3‑4 days from order.
- Can I return it if it doesn't fit?
- Returns are accepted within 30 days of receipt if the lower is unused and in original packaging. A restocking fee of 15 % applies.
- Does this work with a standard 5.56 NATO bolt carrier group?
- Yes, the lower is dimensioned for all standard 5.56 NATO BCGs. The bolt catch pin hole is 3.5 mm, matching common BCG specifications.