I was given a pistol from my Dad before he passed away that his Grandfather carried daily in the late 1880's in the bars he owned in the Chicagoland area. I would like to be able to get all the moving parts to function, the barrel will not rotate and there is a pin unfer the barrel which performs some sort of function but I don't know what, also there is a vertical 'screw' in front of the barrel that is spring loaded as it will 'float' vertically and has a screw top but appears to do nothing...noob needs help, thanks in advance...