Decent kit, but needs improvements - Zaffiri Precision Glock 19 Gen 5 Upper Parts Kit

I recently installed the Zaffiri Precision Glock 19 Gen 5 Upper Parts Kit, and while the quality of most components is solid, I encountered a significant issue with the included recoil spring assembly.

Build Quality & Fitment

The extractor, firing pin, and safety plunger are well-machined and fit without any major issues in both factory and aftermarket slides. The springs had proper tension, and overall, the parts looked well-made. However, the recoil spring assembly was the weak point of this kit.

Functionality & Issues

During initial testing, I experienced cycling and function failures, leading to inconsistent performance. After troubleshooting, I determined that the included recoil spring was the culprit. It was not allowing the slide to fully cycle, which caused failure to return to battery issues. I replaced it with a factory OEM Glock recoil spring, and after that, the pistol ran flawlessly.

Instructor’s Perspective

As a firearms instructor, reliability is my top concern. While most of the kit is well-made and functional, the recoil spring issue is a big downside. If I have to replace a critical component right out of the box, it lowers my confidence in the overall package.

Final Thoughts

The Zaffiri Precision Upper Parts Kit is a decent option for a custom Glock 19 Gen 5 build, but be prepared to swap out the recoil spring for a factory OEM part if you run into cycling issues.

Would I recommend it? With caution. If you’re okay with replacing the recoil spring, the kit is still usable. However, for those looking for a drop-in ready solution, this isn’t quite there yet.