Welcome to the forum.
You have a 2nd Model HAMMERLESS LARGE FRAME TOP BREAK 5th Variaition (1916-1924). With a serial number in the 170K range - it was made early in the range - most likely 1917. The 'black' finish is the correct Blued finish for this period in H&R's history.
That gun was made well into the H&R smokeless/Nitro powder capable era and should be able to handle any modern .32 S&W or .32 S&W Long factory loading - IF - it is in such condition as to be safely shot. If you don't know what to look for, have it checked by a qualified gunsmith.
Speaking of a qualified gunsmith - your gun is screwed up internally. It sounds as though the trigger return spring is broken and/or something in jamming up in the action. There should be a smooth pull to release the hammer and then the trigger should return to position in the trigger guard ready for another shot, without any fiddling around.
In v.good condition, and all is working properly - your gun would be worth around 200 bucks with a premium (collector interest) for the blued finish.
Here's a pic of a couple of mine - these are marked as 3rd Var. but that is incorrect - the pic was taken early in the research process and Bill G. came up with different variations since that time.