I've noticed that theres a lot of talk about weak recoil springs.
When I got my CZ-40, I noticed it had a hesitation, when it went back to battery.
You could actually watch the slide move forward, on some shots.
I found the problem, when I got some EAA mags.
In addition to the catch hole problem, the slide was hitting the back of the mag.
When I used them again, the pistol worked great, and didn't show any signs of hesitation.
I put in a factory mag, and sure enough, every few rounds it would hesitate!
I filed the back of the mag, on the factory mags, and have not had this problem, since.
Something to check, before you replace the recoil spring.
