Oldest gun that I own is a .41 caliber Pennsylvania percussion rifle (circa 1850's), walnut half-stock, German silver stock mountings, in very good overall condition. I shoot it regularly with a heavily patched .395 ball and 40 grains of FFFg.
Oldest cartridge gun that I have is a Trapdoor Springfield .45-70 made in 1873. I have been shooting this one since 1978 or so with cast bullets and black powder charges. Took a bull elk with it about 25 years ago.
Oldest Smith & Wesson that I have is an original Russian .44. Unfortunately it is not in shooting condition, but overall not a bad representative piece.
I like the old stuff!