Can you elaborate on "jamming"?
Is it failing to go into battery or is it double feeding? Or stovepipe issue?
Been doing a LOT of research on CZ firearms lately and been reading that some .40 models have a failure to go into battery (not often, but it happens)... not sure if its the recoil spring or the finish on rails that's the issue. No issues with 9mm though... which is CZ's main caliber of choice. 9mm are pretty much flawless from my research.
Contemplating drinking the Kool Aid and purchasing a CZ soon myself.