its a safety bar its supose to move in and out as you #### the hammer.
I have one just like it on my big gasser 1870s gun.
If its not moveing in and out then something is wrong with the hammer or its bar that goes into the hammer area is worn or busted.
When you pull the hammer back the frist click to load that bar snaps in and then if you drop the gun you wont blow your head across the room splatering brains and eyeballs all over the place.
When the hammers down it should be pokeing out a 1/4 or so then it pops in at the frist #### then out again at full ####.
Only time it should be in flush with the frame is when the hammer is in the safety loading notch position.



























