Note #7. In double action, what gun part, or parts does the trigger hit to force the hammer back?
b) The sear
Note #8. Besides the safety feature of the hammer making contact with the hump on the rebound slide, what gun part acts as an internal safety?
d) The hammer block
Note #10. When the revolver is at rest, what is the correct position of the hammer block?
c) It is situated between the frame and the hammer
Note #11. What gun part pushes on the center pin and allows the cylinder to swing open?
d) The bolt
Note #12. The center pin is one lock on the firearm, what is the other?
c) The locking bolt
If you will go to Numrich Arms (Gun Parts Corp) you can find a schematic of a Smith & Wesson revolver with the parts identified.