And regarding reference to buttplates in post #42, I read that Theodore Roosevelt ordered all his Winchesters... regardless of rifle vs short rifle vs carbine... with shotgun style buttplates. Much better in general, IMO, and not incorrect to the period because Roosevelt did it during the period.
Okay, then there's the U.S. Krag... the "Rough Riders" would've had carbines because although they operated on foot in Cuba, "we trained as cavalry!!!!" as Tom Berrenger played the scene. And I have had occasion to examine Krag rifles and carbines which chambered the same .30-40 Krag round... the differences are rather obvious. But, regarding then-Col. Roosevelt in Cuba, he had a Winchester Model 1895 in .30-40Krag, which was known as .30Govt at the time.