Depending on what grain you're shooting, sounds like the ammo is underpowered. I shoot their 124gr NATO and have never had a problem, but that's loaded to nearly +P pressure. CZs are sprung pretty heavy from the factory, and it sounds like your recoil spring is too strong for that ammo. When it does eject, how far away do the shells land? Per CGW, the optimal distance is 6'-8'. If the gun is barely kicking them out, you may need to swap the recoil spring. Or, just don't shoot that ammo.