when shooting the CZ-* guns, don't use the winchester 147gr ammo - it's waaaaay too hot for it, and will be kicking the #### out of your slide lock's internals. I've lost many a slide lock that way (cracked/broken). The 115gr stuff was great, that's what I prefered.
Keep on eye on where the shell casings are ejecting/landing. If they are hitting the ground more than 5-6 feet away from you, your spring is not strong enough for the ammo, so get a new/replacement spring (I get mine from Wolf Springs) , or try a lower powered load.