80 Percent Lower | 80% Lowers | VERY FAST SHIPPING - polymer 80
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About this product
The ArcForge Arms 80 Percent Lower is a CNC‑machined polymer AR‑15 lower receiver kit designed for fast, legal home builds.
It arrives pre‑drilled, aligns with standard AR‑15 components, and ships within 2‑3 business days to keep your build timeline tight. At 13.8 oz (392 g) and measuring 7.5" × 2.2" × 1.3" (190 mm × 56 mm × 33 mm), it balances durability with lightweight performance.
What is the 80 Percent Lower used for?
It serves as the foundational frame for assembling a complete AR‑15 or AR‑10 platform.
The lower houses the trigger group, pistol grip, and buffer tube, letting you customize the rifle to your exact specifications without purchasing a finished receiver.
How does the 80 Percent Lower compare to the Polymer80 PF940V2?
It is 1.2 oz lighter and 0.4 in shorter than the Polymer80 PF940V2, making it marginally more ergonomic for compact builds.
Both kits include the same jig and hardware, but ArcForge’s tighter tolerances reduce post‑machining work by roughly 15 %.
What does it weigh and what are the dimensions?
The lower weighs 13.8 oz (392 g) and measures 7.5" × 2.2" × 1.3" (190 mm × 56 mm × 33 mm).
This size fits standard AR‑15 stocks and buffer tubes while keeping the overall rifle weight under 6 lb when assembled.
Who is this NOT for?
It is not suited for shooters who require a fully finished receiver out of the box.
If you lack basic tools like a drill press or a jig, the additional machining step may add extra cost and time.
What's in the box?
The package contains the polymer lower, a precision jig, six pan head screws, a stainless‑steel buffer tube, and a full PDF of assembly instructions.
The jig aligns the lower’s internal cutouts to +/-0.002" tolerance, cutting repeatable fit for the trigger group.
Is the 80 Percent Lower worth it at $129?
Yes, because you save $150‑$200 versus buying a completed lower of comparable quality.
At $129 you receive a ready‑to‑machine kit with factory‑tested tolerances, fast shipping, and a 30‑day return policy.
For a detailed look at shipping timelines, see our Bulk Order Lead Times article. Compare this kit to the .308 80% Lower – Billet for a metal alternative.
Specs at a glance
Pros & cons
What works
- Weighs 13.8 oz — 1.2 oz lighter than Polymer80 PF940V2
- Ships in 2‑3 business days — faster than most competitors
- Includes precision jig that reduces machining time by ~15 %
Trade-offs
- Requires a drill press or jig to complete the final cut
- No stippling or surface finish — adds $40‑$80 if you want custom texturing
- Limited to 5.56 mm builds; not compatible with 6.8 mm or larger calibers
Key attributes
| Caliber | 5.56 NATO |
| Weight | 13.8 oz (392 g) |
| Dimensions | 7.5" x 2.2" x 1.3" (190 mm x 56 mm x 33 mm) |
| Material | High‑impact polymer |
| Condition | New |
| Compatibility | Standard AR‑15 components |
Frequently asked questions
- Is it compatible with an AR‑15 buffer tube?
- Yes, the lower is machined for a standard Mil-Spec buffer tube. It fits tubes ranging from 1.1" to 1.2" in diameter, which covers 95 % of aftermarket options.
- Does it fit a Magpul MIAD stock?
- It does. The lower’s buffer tube thread matches the MIAD's 1.0"‑13.5 thread, allowing direct installation without adapters.
- How long does shipping take?
- Standard shipping averages 2‑3 business days from our Nevada fulfillment center, with a typical delivery window of 5‑7 days nationwide.
- Can I return it if it doesn't fit?
- Yes, you have 30 days for a full refund provided the lower is returned in its original condition and packaging.
- Does this work with a standard AR‑15 trigger set?
- It does. The lower accepts any standard 5.56 mm trigger group, and our internal dimensions are calibrated to 0.001" tolerance for reliable function.