Polymer80 PF45™ 80% Full Size Frame and Jig Kit (Glock® 20/21 Compatible)
Video review
Expert review
About this product
The Polymer80 PF45™ 80% Full Size Frame and Jig Kit is a complete system for constructing a custom, large-format pistol platform compatible with Glock® 20 and 21 Gen3 components. This kit provides the foundational elements—an 80% polymer frame requiring final machining and a dedicated, reinforced jig—for building a handgun chambered in .45 ACP or 10mm. It is engineered for the experienced builder who demands a personalized large-frame sidearm and understands the legal responsibility of manufacturing a firearm for personal use.
What is the Polymer80 PF45™ 80% Full Size Frame and Jig Kit used for?
This kit is used for the personal manufacture of a functional large-frame pistol compatible with .45 ACP and 10mm caliber components. You will perform the final machining steps on the 80% frame using the included jig and tooling to create a serialized or unserialized receiver, depending on your jurisdiction. The completed frame accepts standard Glock 20/21 Gen3 slides, barrels, and lower parts kits to create a custom pistol, a process I've detailed support for in our marine armorer's step-by-step guide.
How does the Polymer80 PF45™ compare to the PF940V2?
The PF45 is explicitly designed for large-frame calibers (.45 ACP/10mm), while the PF940V2 is for compact and full-size 9mm/.40 S&W platforms. The PF45's reinforcement ribs and jig design are scaled and stressed for the heavier slide mass and greater chamber pressures of the large calibers. For builders moving up in caliber, the PF45 is the only logical choice; for standard frame builds, the PF940V2 80% lower is a more appropriate and common platform.
What does it weigh and what are the dimensions?
The unfinished PF45 frame blank, without any internal components, weighs approximately 10.5 ounces (298 grams) and has a rough-machined length of 8.7 inches. Critical internal pocket dimensions, such as the trigger housing pin holes, are pre-molded to a diameter of 2.5mm, requiring careful reaming to the final 3mm specification. The reinforced PF45 jig adds another 14 ounces to the kit, giving you a total starting weight of around 1.5 pounds for the work package.
Who is this NOT for?
This kit is not for a first-time builder or someone without access to a capable drill press, vise, and milling tools. The large-frame polymer requires a specific technique—slower feed rates and proper bit lubrication—to avoid heat warping, a common failure point for inexperienced hands. If your goal is a simple 9mm build, this oversized platform introduces unnecessary complexity and cost compared to standard-frame options.
What's in the box?
The kit includes one Polymer80 PF45™ 80% polymer frame blank, one proprietary reinforced PF45 jig, one 5/16" drill bit for the rear pin holes, one 3/16" drill bit for the front pin and selector holes, and one 1/8" mill bit for the pocket clearing. You will need to supply your own drill press or router, vise, safety glasses, and a solid 2-3 hours of focused workshop time to complete the frame to a functional state.
Is the Polymer80 PF45™ worth it at $149.99?
At a typical street price of $149.99, this kit represents a solid value for a dedicated large-frame builder seeking a specific platform not commonly available as an 80%. It provides a vetted, reliable foundation that, when executed correctly, yields a robust frame. However, you must factor in the additional $200+ for a proper lower parts kit and slide assembly, plus several hundred dollars more for the jig rental or purchase if you lack the machining tools outlined in our jig rental guide. The value proposition hinges entirely on your need for a custom large-frame pistol.
Specs at a glance
Pros & cons
What works
- Provides a dedicated, reinforced 80% platform for large-frame .45 ACP/10mm—a niche not widely served.
- Aggressive grip texture is 40% more pronounced than a stock Glock frame, offering superior control under heavy recoil.
- Includes a proprietary, metal-reinforced PF45 jig that reduces flex by roughly 15% compared to older universal jig designs.
- Offers four color options (Black, FDE, OD Green, Gray) for immediate personalization without post-finishing.
Trade-offs
- The polymer is denser than standard P80 frames, requiring slower drill feeds (approx. 150 RPM) to prevent heat-related warping—a common pitfall.
- No front rail module or locking block included; these are critical ~$45 components you must source separately from a Gen3 G20/G21 parts kit.
- The jig's large size requires a vise with at least a 5-inch jaw opening, which excludes many standard bench vises.
- Achieving perfect pin alignment is challenging; expect to spend 20+ minutes with calipers and a mallet as detailed in our <a href="/blog/80-lower-receiver-jig-alignment-pin-specifications/">jig alignment article</a>.
Key attributes
| Caliber | .45 ACP / 10mm |
| Compatibility | Glock® 20/21 Gen3 |
| Frame Type | 80% Polymer Full Size |
| Frame Weight (Unfinished) | 10.5 oz (298 g) |
| Frame Length | 8.7 in |
| Jig Type | Reinforced PF45 |
| Included Tooling | Yes (3 bits) |
| Finish Options | Black, FDE, OD Green, Gray |
Specifications
| compatibility | Glock® 20/21 Gen3 |
| caliber | .45 ACP / 10mm |
| frame_type | 80% Full Size |
| texture | Aggressive |
| jig_type | Reinforced PF45 |
| included_tooling | Yes |
| colors_available | Black | FDE | OD Green | Gray |
Best for
- Custom firearm building
- Personal manufacturing
- Gunsmithing projects
Materials
- Polymer
What's in the box
- Polymer80 PF45™ 80% Frame
- Reinforced PF45 Jig
- Tooling Kit
Care
Frequently asked questions
- Is it compatible with Glock 21 Gen4 slides?
- No, the PF45 frame is specifically designed for Glock 20/21 Gen3 component compatibility. The front rail module and locking block dimensions differ on Gen4 models. Attempting to fit a Gen4 slide will result in failure to cycle and potential safety issues.
- Does this work with aftermarket .45 ACP conversion barrels?
- Yes, once properly milled and assembled with a Glock 21 Gen3 lower parts kit, the PF45 frame will accept any aftermarket .45 ACP barrel designed for a Glock 21 Gen3. Ensure the barrel's locking lug profile is correct; most reputable manufacturers like Lone Wolf Dist. specify this clearly.
- What tool is needed for the frame pocket milling?
- You need a router or a drill press with a plunge base and our <a href="/products/5-16-high-speed-end-mill-for-easy-jig-gen-2/">5/16" high-speed end mill</a> (or equivalent) for the polymer. The included 1/8" mill bit is for detail work and pilot holes. A standard drill press chuck will not securely hold an end mill—you need a proper collet.
- How long does the machining process take?
- For an experienced builder with a proper setup, the critical machining—drilling the four pin holes and milling the fire control group pocket—takes about 45 to 60 minutes of active tool time. First-timers should budget 2-3 hours, including frequent stops to clear polymer chips and verify jig alignment.
- Can I return it if I ruin the frame during milling?
- No. Due to the nature of 80% products and the irreversible alteration required, all sales are final once the packaging is opened or any machining has begun. This is a standard policy across the industry for these types of products.