One of the problems you might encounter using buckshot is that I have heard that the stuff you buy these days tends to have a fair amount of antimony in it which would probably make it hard enough so that it would be difficult to load in those little revolvers. I would have to check, and its been awhile since I have shot my uberti 31's, but I think I was finding that I got better performance with .315 diamteter round balls. If I recall .310 never seemed to be a good fit in the chamber.