I don't know the dimensions of the 38-40 cartridge---but Google does.
As to other revolvers chambered for the 38-40, the Triple Lock, the .44 Double Action 1st Model, at least one NM #3 Target (#3914) that lived here for a spell -------and lettered as "-----------appears to have been a special order for one unit---------------." (Anomalies such as this are explained by one of Jinks' oft used explanations, "They would do anything anybody would pay them to do.") And seems like the SCSW speaks of a batch of NM #3's numbered from 1 to 74 in 38-40. Beyond that, I'm pretty much like you. I've seen only the one I mentioned above, but I was treated to shooting a big thumping Colt in 38-40 when David Carroll and his grandson stopped by on their way to the Smokies for some bear watching. He'd brought along a bunch of different guns, and A BUNCH of ammo for all of them, with the instruction to "Shoot it up!", I mowed off a lane in the front field, set up some target stands, and we did as we were told. One of the guns was a Schofield, along with an almost full box of ammo, which he described as "I don't know if these are factory or reloads, but shoot'em up!" Near as I recall two rounds went BANG, and the rest went CLICK, but I could say I'd fired a Schofield.
Ralph Tremaine
