Believe me, I have tried different springs. I have the original as I didn't want to modify that. I am now on my 4th spring. As the hammer pivots, the "shelf" moves to the rear. The cutting of the "shelf" seems to be working....to a degree. I can now (forcefully!) cock the hammer. The trigger pull is about 90 pounds! In fact, I can't pull it with my finger. I had to use pliers! And so the process continues....