The 500's....500 S&W, 500 JRH, 500 WY Express, 50 Action Express.
The 510... 500 Linebaugh
500 S&W needs the big S&W X-Frame in a DA or a Magnum Research BFR or a custom stretch frame by Gary Reeder.
500 JRH was designed by Jack Huntington to bring a Fifty to the Freedom Arms revolver. Mr. Huntington can convert your FA 83.
500 Wyoming Express is a belted cartridge designed by Freedom Arms for their fine revolvers.
50 Action Express is has a rebated rim and headspaces on the case mouth like the 45 AUTO. It can be had in a Desert Eagle Auto loader as well as FA revolvers and custom revolvers such as a custom Redhawk by Hamilton Bowen.
500 Linebaugh is actually a 51 caliber. It was designed by John Linebaugh. This is the largest calber handgun cartridge made and can be had in a custom Blackhawk revolver. The are many fine gunsmiths that make these bigbore conversions.
Any of these will do the job. I hope to find out first hand what the 500 Linebaugh is capable of.
EDIT.... Whitworth one who shoots and hunts with these boomers added this since I overlooked it.