Re: Old gun, loaded in the front. (sorry for the english, i am danish)
The term you wanted was "muzzle loader".
It's not an old gun. If it was, it would have been handmade, would not have a serial number, and would not say "black powder" on it. Back then black powder was the only kind, so there was no need to put that warning on the guns.
You have a modern replica, worth, maybe 75 dollars.
Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297
I always take precautions.
Beware the Evil Bullet Fairies.