My 2002 75 40B was also plagued every 20-30 rounds fired. Polished ramp and after problem repeatedly happened I wrote email to CZ and their gunsmith sent a new Wolf ejection spring to correct Failure to Eject spent and round hanging on ramp combination. Because this 40 has been totally unlike my CZ 75 9mm was as far as reliability, I bought a Glock 23 for Home Defense and reliability.
Just got around to replacing spring and I'm going to post new findings afterwards.
Before anyone asks about types of loads, I did try WinchesterRange rounds as well as Federal Hydroshock rounds and the stovepipe/ fail to feed continued intermittently.
If anyone else has had same issues please reply as I'm almost ready to do the unthinkable and sell it or trade for an operational Rami .40 if spring replacement "Fails to Fix".