Personally I'd like to have a Sharps in .50-90, and I've nearly jumped on a couple of them. The .50-140 is too much of a good thing, even with black powder.
I've shot a Verney Caron .577 Nitro double, and despite weighing 14 lbs one shot was quite enough.
A .470 Nitro double was not bad at all. My .475 Turnbull #1 - which is basically a short .470 Nitro - is not bad, even though it weighs only 9 lbs with scope & mounts. So I guess a .500 Nitro #1 might be tolerable. For once I might pick the truck axle D weight barrel.
The traditional British single shots, like the Fahrquharsen, the Henry, or the Field's Patent, I think are more appealing in the big Nitro calibers. But of course originals and reproductions tend to be expensive. A Shiloh is a bargain in comparison...and makes the same size holes
