The GLOCK 21GEN4 is a full-size .45 ACP pistol built on the proven Gen4 platform. It’s for shooters who want reliable, high-capacity .45 performance with the improved ergonomics and modular backstraps of the fourth generation. Since adding it to our inventory in summer 2025, it has consistently been a top seller and a regular reorder item for our warehouse.
Stand-Out Features
- Gen4 Ergonomics: Modular backstrap system allows you to customize grip size and feel to fit your hand.
- Rough Textured Frame: Enhanced RTF (Rough Textured Frame) provides a more secure grip in all conditions.
- Dual Recoil Spring: The captive dual recoil spring assembly reduces felt recoil and increases service life.
- High Capacity .45: Standard 13-round magazine capacity in a proven .45 ACP platform.
- Proven Reliability: Built on the GLOCK Safe Action system known for consistent performance.
Technical Data
| Caliber | .45 ACP |
| Barrel Length | 4.61″ |
| Overall Length | 8.07″ |
| Height | 5.51″ |
| Width | 1.34″ |
| Weight (measured) | 3.6 oz |
| Magazine Capacity | 13 Rounds |
| Frame Material | Polymer |
Your Questions Answered
What backstraps are included?
The GLOCK 21GEN4 ships from the factory with multiple interchangeable backstraps (beavertail and standard) to adjust grip size and angle to your preference.
Is this California compliant?
No, this model is not on the California Roster of Handguns Certified for Sale. Please verify all local and state laws before ordering.
What’s a common upgrade for this model?
Our staff notes that many customers pair this with an extended slide release for faster, more positive manipulation during reloads.
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