Polymer80 G150 AR15 80% Lower Receiver ONLY - polymer 80
Pros & cons
What works
- Weighs 6.8 oz — 7.4 oz lighter than aluminum .308 billet lower
- Saves $40-65 versus typical aluminum 80% lowers
- Maintains MIL-SPEC dimensions within 0.005-inch tolerance
Trade-offs
- No jig included — adds $65 minimum to complete project
- Polymer softens above 200°F — unsuitable for sustained full-auto fire
- Impact resistance 30% lower than 7075-T6 aluminum per ASTM testing
Video review
Expert review
Specs at a glance
About this product
What is the Polymer80 G150 AR15 80% Lower Receiver ONLY? It's a polymer-based 80% lower receiver designed for AR-15 platform builds requiring user completion. Unlike traditional aluminum receivers, this model uses Polymer80's proprietary polymer blend, reducing weight by approximately 40% compared to standard forged aluminum lowers. Production has been temporarily halted, making current inventory part of final sales batches.
What is the Polymer80 G150 used for?
The Polymer80 G150 is used for building custom AR-15 rifles without serialization requirements. It requires milling of the fire control group pocket and drilling of pin holes using a jig (sold separately). The polymer construction makes it ideal for lightweight build projects where 6.8 ounces matters more than extreme durability. Complete builds typically weigh 1.2-1.5 pounds less than aluminum-based equivalents.
How does the Polymer80 G150 compare to the .308 80% Lower – Billet?
The Polymer80 G150 weighs 6.8 ounces compared to the 14.2-ounce .308 80% Lower – Billet. The billet aluminum alternative provides superior impact resistance and thermal stability but adds 7.4 ounces to final build weight. For caliber-specific applications: the G150 handles 5.56/.223 exclusively, while the billet model accommodates .308/7.62x51mm rounds.
What does it weigh and what are the dimensions?
The Polymer80 G150 weighs 6.8 ounces with dimensions measuring 7.5 inches long, 2.1 inches wide, and 1.5 inches thick. These measurements mirror MIL-SPEC AR-15 lower receiver dimensions within 0.005-inch tolerance. The weight reduction comes from polymer composition rather than dimensional changes, maintaining compatibility with standard upper receivers and buffer tubes.
Who is this NOT for?
This receiver is not for builders requiring extreme durability under sustained full-auto fire or environments exceeding 200°F. Polymer softens at lower temperatures than aluminum, potentially affecting pin hole alignment during extended rapid fire sessions. For high-heat applications, the billet aluminum alternative maintains structural integrity better above 180°F.
What's in the box?
The box contains only the 80% lower receiver without jig, tools, or instructions. You receive one polymer lower weighing 6.8 ounces, requiring separate purchase of a compatible jig ($45-75) and machining tools. Completion typically requires 2-3 hours of milling work using a drill press or router with appropriate carbide bits.
Is the Polymer80 G150 worth it at $55.99?
At $55.99, the Polymer80 G150 offers 40% cost savings versus typical aluminum 80% lowers averaging $95-120. The trade-off involves accepting polymer's temperature limitations and reduced impact resistance. For builders prioritizing weight reduction and cost over extreme durability, the value proposition justifies the price during this final sale period.
Key attributes
| Caliber | 5.56 NATO / .223 Remington |
| Material | Polymer80 proprietary polymer |
| Weight | 6.8 oz |
| Finish | Matte black |
| Completion | 80% requires machining |
| Dimensions | 7.5 x 2.1 x 1.5 inches |
Frequently asked questions
- Is it compatible with standard AR-15 parts?
- Yes, the Polymer80 G150 uses MIL-SPEC dimensions compatible with standard AR-15 upper receivers, buffer tubes, and fire control groups. Pin holes require drilling to 0.154-inch diameter using included jig alignment. All critical interfaces match standard AR-15 specifications within 0.005-inch tolerance.
- Does it come with a jig?
- No, this is receiver-only product requiring separate jig purchase. Polymer80 sells compatible jigs for $64.995D Tactical or Modulus Arms may work with modification. Completion without proper jig risks misaligned pin holes rendering receiver unusable.
- How long does shipping take?
- Standard shipping takes 7-10 business days within continental US, with expedited options available for additional $18.95. All shipments require signature confirmation upon delivery. International shipping unavailable due to export restrictions on 80% receivers.
- Can I return it if I damage during milling?
- No, all 80% receiver sales are final once machining begins. Returns only accepted for unmodified receivers within 14 days of receipt. Damage during completion voids any warranty claims—practice on cheaper polymer blanks first if new to machining.
- Does this work with drop-in triggers?
- Yes, but requires precise milling of fire control pocket to specific dimensions. Drop-in triggers like CMC 3.5-pound single-stage need pocket depth of 1.125 inches minimum. Measure twice before cutting—polymer won't tolerate over-milling like aluminum can.