CZ seems to not do nearly as well with .40 Cal, I have newer 2nd gen that came with extended base plates and a comp hammer and it has too weak of a recoil spring.
I probably make it through 1 out of 3 magazines without a malfunction namely the slide locking back prematurely.
I would be cautious venturing away from 9mm in CZ.
There is some truth here. I have over 20 CZs in the family and of those, the 9mm ones have never given me a single issue outside of the time I tried Froglube on a compact. The .40s have been hit or miss in reliability. Both of my .40 P09s are perfect and have been from round one. My 75B in .40 has been perfect as well. Both of my P07s in .40 have had issues and I run a heavier recoil spring in them to help tame slide velocity to keep them happy. My 75B Compact in .40 has been awful from day one though. I have a 40P that?s perfect once I installed a SS guide rod. That 75B Compact in .40 is bad enough that I sources a spare 40P slide and am running that on it with good results.
9mm is definitely CZs strong area, but when the P07s are running well, they really run sweet. You just have to keep up with spring change intervals on those and need to be careful with tuning as a lighter mainspring can induce feed issues.
