FWIW, My Cooey Model 60 and Henry Golden Boy both feed shorts just fine.
Winnipeg Toymaker might have a point when he says,
"the casings and bullets are shorter and leave more space between the casing and barrel throat for residue to pile up."
My Cooey has got to be at least 40 years old, shot most of it's life with shorts and I don't think it's any worse for wear because of it. It's in very rough shape, but that's because it was rarely cleaned and was probably used as a fence post for a good portion of it's life. As far as I can see, the throat looks pretty good.