i have been having a problem with my sp101 recently. when firing double-action, there seems to be no problem, however, sometimes, when i try shooting it single action and thumb cock it, the hammer will hit a snag, and the hammer can only be pulled back about 3/4 inch. it doesn't get stuck in this position, and if i lower the hammer, and recock it, it will work. this doesn't happen all the time, but it will happen once in 2-3 cycles of the cylinder, this made me nervous, so i took the gun apart, and i discovered that the "hammer-dog" had deep vertical gouges tooken out of it. does anybody know if this problem will go away, or if i need a new hammer and hammer dog. what can i do? please help