Actually, I think that is standard 500 S&W Magnum rounds. Having shot the S&W pistol, I think the rifle would be a easier!
I have both the 460 and 500 S&W revolvers. I also have TC Encore rifle frames with barrels for 460 and 500 S&W Magnum. The rifle format delivers more punch. Good ammo for either one is very expensive. I reload ammo for plinking. The factory loads for hunting are significantly better quality in both bullet and powder volume. The TC for 460 can also launch 454 Casull and 45 Colt. For those who don't like the vicious recoil of the 500 S&W Magnum, there are 500 SPL loads. Same concept as 357 magnum/38SPL. Shorter case, lighter bullet, less powder.
My Magnum Research BFR in 45/70 is a fairly potent revolver as well. Suitable for moose. I hand load plinkers for that one tool. It's a little more trouble because of the case size. You MUST use case lube on the brass before resizing or expect a stuck case in your resizing die. Too much lube and you get "lube dimples". Too little and you get a stuck case. Mine has the 3 inch cylinder and I think the 10 inch barrel. The only caveat with factory ammo is a 31,000 PSI pressure limit. It can't handle T/C Encore pressures. The 1895GM rifle handles pressures between 31,000 PSI and the T/C Encore limits.