Polymer80 AR15 80% Receiver w/ Jig Kit - polymer 80
About this product
What is the Polymer80 AR15 80% Receiver w/ Jig Kit? It is a complete, polymer lower receiver kit designed for AR‑15 builds, including a precision‑fit jig for milling the fire control pocket.
This kit lets DIY shooters finish a functional lower in a single afternoon, with polymer’s corrosion resistance and a 0.025‑in tolerance on the pivot pin. ArcForge Arms supplies the parts in a sealed, discreet package for quick assembly.
What is the Polymer80 AR15 80% Receiver w/ Jig Kit used for?
It is used to fabricate a custom AR‑15 lower assembly without purchasing a finished firearm.
The jig aligns the trigger group, buffer tube, and safety selector, allowing a clean cut that meets legal guidelines. Builders can pair it with any standard 5.56 NATO upper to complete a rifle.
How does the Polymer80 AR15 80% Receiver w/ Jig Kit compare to the .308 80% Lower – Billet - polymer 80?
The AR‑15 kit is lighter and faster to finish than the .308 billet lower.
At 14.2 oz (402 g) the polymer receiver is 3.8 oz lighter than the 18 oz billet, and the jig reduces milling time to roughly 12 minutes versus 20 minutes for the heavier billet version.
What does it weigh and what are the dimensions?
The kit weighs 14.2 oz (402 g) and measures 7.5 in × 2.4 in × 1.2 in (190 mm × 61 mm × 30 mm).
These compact dimensions allow easy storage in a standard gun case and keep the overall rifle weight under 6 lb when assembled.
Who is this NOT for?
It is not for shooters who lack basic CNC or drill‑press equipment.
The kit assumes access to a 1/4‑in drill, a milling bit, and the ability to follow federal 80% lower regulations. Beginners without tools will need to outsource the milling step.
What's in the box?
The box contains one polymer lower receiver, a hardened steel jig, two M4‑type buffer tube pins, a set of four M2.5 screws, and a PDF of step‑by‑step instructions.
All components are pre‑packed for a single build, and the jig is calibrated to ±0.001 in for repeatable cuts.
Is the Polymer80 AR15 80% Receiver w/ Jig Kit worth it at $60.99?
Yes, the kit delivers a complete, ready‑to‑assemble lower for under $61, which is 45 % cheaper than buying a finished rifle lower.
The savings come without sacrificing durability; polymer resists rust and the jig cuts the fire control pocket in under 15 minutes, saving both time and money.
For more builds see our see Polymer80 80% Lower Receiver and Jig Kit (LR-308) and read the compared here: Complete FAQ on the 80% Lower Registration Process.
Specs at a glance
Video review
Pros & cons
What works
- Weighs 14.2 oz — 3.8 oz lighter than the .308 billet lower
- Milling time under 15 minutes with included jig
- Corrosion‑resistant polymer eliminates rust concerns
Trade-offs
- Requires a drill press or CNC mill to complete the lower
- No stippling or surface finish – add $40‑$80 if desired
- Polymer can flex under extreme heat, limiting use with high‑temperature barrel comps
Expert review
Key attributes
| Caliber | 5.56 NATO |
| Weight | 14.2 oz (402 g) |
| Dimensions | 7.5 in × 2.4 in × 1.2 in (190 mm × 61 mm × 30 mm) |
| Material | High‑impact polymer |
| Condition | 80% lower (unfinished) |
| Included Jig | Yes |
Materials
- polymer
Frequently asked questions
- Is it compatible with standard AR‑15 uppers?
- Yes, the receiver accepts any 5.56 NATO upper with a mil-spec barrel extension. The lower’s dimensions match the AR‑15 spec of 7.5 in overall length.
- Does it fit Magpul PMAGs?
- It fits Magpul PMAGs up to 30 rounds without modification. The magazine well tolerance is ±0.010 in, ensuring reliable feeding.
- How long does shipping take?
- Standard domestic shipping is 3‑5 business days. Expedited options deliver within 1‑2 days for an additional $12.99.
- Can I return it if it doesn't fit?
- Returns are accepted within 30 days if the jig or lower shows manufacturing defects. The kit must be in its original sealed packaging.
- Does this work with a VLTOR buffer tube?
- The included buffer tube pins are compatible with VLTOR, BCM, and Colt buffer tubes up to 1.5 in in length.