From my personal experience on all the untouched CZ 75 SP-01 Shadows I've fiddled around with you CANNOT engage the safety while the hammer is fully decocked. They are designed that way from the factory. IF you change the hammer, sear or the safety (OEM parts) you will have small tolerances and/or if you have to fit the sear/safety engagement points you can easily have a gun that can engage the safety while the hammer is fully decocked. It is a matter of tolerances between parts and/or if someon