I would go with an inline muzzle loader, shotgun primer. Fairly modern and not meeting the nostalgic requirement, on the other hand, easy to set up, very reliable and very accurate to shoot even with open sights up to 100 yards. I recommend this model. It sells for under $150 in the blued version!
http://www.bfgoodrichtires.com/images/tire-selector/tires/all-terrain-t-a-ko.jpg
Caliber 50, load up with sabot .44 caliber bullets. 100 grains of Pyrodex pressed pellet powder and you will be ready to go deer hunt. Expect it to group at 4" or less at 100 yards.
Hope this helps. I am no expert but the above has worked very well for me - except for the elk not cooperating.
George