I have 3 CZ's and all have the stock recoil springs. I run only reloads using 115 HAP bullets and sometimes I use 124/127 grainers just for a change. All three of my CZ's have optics on them and I have never had a problem with them. I am not interested in PF details, just best accuracy for paper punching. While my Shadow 2 OR and Shadow 2 Carry are very accurate, my TSO is the one that takes the cake for accuracy from a rest. It has far more accuracy potential than I can muster from it shooting off-hand and I equate some of that to my reloads (hopefully), but I have never had a 9mm handgun shoot as well as my TSO. It's an amazing pistol.
Rick H.