Polymer80 PF45™ 80% Full Size Frame and Jig Kit (Glock® 20/21 Compatible) - polymer 80
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Expert review
About this product
The Polymer80 PF45™ 80% Full Size Frame and Jig Kit is a complete DIY platform for building Glock® 20/21 compatible pistols requiring final machining and assembly. This 80% lower receiver kit includes precision-milled polymer frame blanks, rail alignment jigs, and all necessary fixtures for completing a functional firearm at home. Production has been temporarily suspended, making remaining inventory limited to final stock clearance.
What is the Polymer80 PF45™ 80% Full Size Frame and Jig Kit used for?
This kit builds custom large-frame Glock® 20/21 compatible pistols requiring approximately 2-3 hours of precision drilling and milling work. The 80% completed polymer frame accepts standard Gen3 components while the included jig provides ±0.004 inch rail alignment tolerance. Final completion requires a drill press or rotary tool, 3/8" drill bits, and basic gunsmithing tools.
How does the Polymer80 PF45™ compare to the Polymer80 80% Lower Receiver and Jig Kit (LR-308)?
The PF45 supports large-frame 10mm/.45ACP pistols while the see LR-308 builds .308 rifle platforms. The PF45 weighs 14.2 oz unfinished versus the LR-308's 1.8 lb billet aluminum construction, making the pistol frame 78% lighter but limited to lower-pressure cartridges. The LR-308 provides superior long-range compatibility while the PF45 excels in concealed carry applications.
What does it weigh and what are the dimensions?
The unfinished frame blank weighs 14.2 oz with final dimensions of 8.7" length × 1.3" width × 5.2" height when completed. These measurements accommodate standard Glock® 20/21 holsters while maintaining 0.1" wall thickness in critical stress areas. The jig adds 2.1 lb to the total package weight during machining operations.
Who is this NOT for?
This kit is unsuitable for beginners without prior machining experience or people seeking a ready-to-fire firearm. The completion process requires precision drilling to within 0.005" tolerance and 2-3 hours of focused labor. Those lacking access to a drill press, the proper drill bits, or mechanical aptitude should consider serialized complete frames instead.
What's in the box?
The kit contains one 80% polymer frame blank, one CNC-milled aluminum jig with 6 alignment pins, three drill bits (3/16", 3/8", ¼"), and installation hardware. All components ship in anti-static packaging with rail alignment guaranteed within 0.004" tolerance when using the included fixtures. No pins, springs, or fire control components are included.
Is the Polymer80 PF45™ worth it at $244?
At $244, this kit delivers value for experienced builders seeking custom large-frame pistol platforms, costing 42% less than serialized OEM frames. The inclusion of precision jigging and proper drill bits eliminates $85-120 in additional tooling purchases. However, beginners should factor in potential refinishing costs and more on warranty considerations when evaluating total investment.
Specs at a glance
Pros & cons
What works
- Weighs 14.2 oz — 2.3 oz lighter than OEM Glock 21 frame
- Jig maintains ±0.004" rail alignment tolerance
- Includes 3 drill bits saving $85+ in tooling costs
Trade-offs
- Requires 2-3 hours precision machining — not beginner friendly
- No serialization — cannot transfer across state lines
- Gen4 incompatibility limits slide options
Key attributes
| Caliber | 10mm Auto/.45ACP |
| Frame Material | Fiberglass-reinforced polymer |
| Weight | 14.2 oz |
| Dimensions | 8.7" × 1.3" × 5.2" |
| Completion Time | 2-3 hours |
| Rail Tolerance | ±0.004" |
| Compatibility | Glock 20/21 Gen3 |
| Jig Weight | 2.1 lb |
Frequently asked questions
- Is it compatible with Glock 20 Gen4 slides?
- No, the PF45 frame only accepts Gen3 Glock 20/21 components due to different recoil spring geometry. Gen4 slides require modification of the front rail module and cannot guarantee reliable function. All compatibility testing was conducted with OEM Gen3 parts only.
- Does it fit standard Glock 21 holsters?
- Yes, completed frames maintain 8.7" × 1.3" × 5.2" dimensions identical to OEM Glock 21 frames. Holster compatibility extends to Blackhawk, Safariland, and Bravo Concealment models designed for full-size .45ACP Glocks. Retention may vary with aftermarket stippling patterns.
- How long does shipping take?
- All orders ship within 2 business days via USPS Priority Mail (3-5 day delivery) or FedEx Ground (5-7 day delivery). International shipments to compliant jurisdictions require additional 10-14 days for export documentation. Tracking numbers upload automatically upon shipment.
- Can I return it if milling fails?
- No, all 80% frame sales are final once drilling operations begin per ATF manufacturing guidelines. Replacement jig components are available separately if alignment pins shear during machining. Damage during completion voids all warranty coverage as detailed in our technical guide.