I think the 460 might have a bit too much pressure for the Handi. It's (the 460) is rated to 65K PSI and with that large of a case head I doubt you'd have a rifle worth shooting after a few shots.
When S&W made the 460, the started with the same gun used for their 500. They quickly found out the backthrust was so great, it imprinted the firing pin bushing onto the back of the case. They had to bake the pin bushing larger than the case head, and use a much harder material.
They had severe gas cutting issues with it on the back of the barrel and had to actually polish the minute machine marks off the back of the barrel to prevent them from "channeling" the gasses.
I'd suggest, if you want one really bad look into a TC Encore, I think they have a 460 barrel.