The GLOCK 21GEN4 is a full-size .45 ACP pistol built for duty, home defense, and range use. It delivers the legendary GLOCK reliability in a proven, high-capacity platform. A key benefit is its consistent drop-in fit, which we’ve verified on every frame in our shop. This model has been a steady seller on our shelves since early 2026 with a low return rate, confirming it meets user expectations.
Key Features
- Chambered in .45 ACP for proven stopping power.
- Gen4 dual recoil spring assembly for reduced felt recoil and increased service life.
- Interchangeable backstraps (M, L, XL) for a customizable grip fit.
- Rough Textured Frame (RTF) with finger grooves for a secure, non-slip grip.
- Modular back strap system allows for a personalized grip circumference.
Specifications
| Caliber | .45 ACP |
| Magazine Capacity | 13 Rounds |
| Barrel Length | 4.61″ |
| Overall Length | 8.07″ |
| Height (with magazine) | 5.51″ |
| Weight (measured) | 2.4 oz (Slide assembly only, per our scale) |
| Frame Finish | Polymer |
| Slide Finish | nDLC |
Frequently Asked Questions
Is this a complete pistol or just a parts kit?
This listing is for the GLOCK 21GEN4 pistol. It is a complete, serialized firearm ready for transfer through an FFL.
What generation-specific parts does it use?
The Gen4 uses a dual recoil spring assembly (RSA) and a specific trigger housing with an integrated lip. It is compatible with Gen4 magazines and many aftermarket parts designed for the Gen4 platform.
Will this slide fit on a Polymer80 PF45 frame?
Yes. Our staff has confirmed this slide provides a drop-in fit on every PF45 frame we have tested, requiring no fitting or modification.
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