First make sure you have it positioned correctly, new spring(s) for the firing pin(s)....The round piece that holds the pins is called a firing pin bushing, it hold the springs and the pins in from the breech side with the screw coming in from behind under the hammer. If you have the hammer out (which by the way is the only way to do this job) you should be able to access the screw while holding the parts all in correctly from the breech side. Actually the trickiest part is assembling the hammer/spring back in the gun. You will need a piece of round rod 3/16" in diameter 3/8" long. Put the hammer and spring together with this ...outside of the gun, push this into the frame lining up the hole in the frame with the short pin holding the two together. Use the original gun pin to carefully punch out the short pin and position the gun pin....I have not found another way to do this.