My grandfather had a large (50+) firearm collection. He passed away about 25 years ago and the relatives sold off most of it at that time. I just recently found out there were a few left and have been able to acquire them. I had no idea what was there but found some surprises when I got them. The one relevant to this forum is a Thompson Center Arms 50 Caliber muzzle loading rifle with an octagon barrel. I was told that my grandfather called it a "Buffalo gun". No idea if this is just a nick name he used or possibly what it was originally sold as. It looks to be in very good condition. No apparent rust anywhere. Any idea what something like this might be worth?