I went out for a shooting session this past week with my TSO 9MM. No problems. Cleaned the pistol when I got home, re-assembled it and couldn't release the hammer. Yep, broken trigger return spring. Called CZ, I didn't have the SN with me at the time, so I'll call them again Monday with the SN and they'll send one out. This is a first for me with my CZs. Is this pretty common?