The 454 casule did not make the list but it is a hand cannon. If you don't want the discomfort or the expense of the cartridges you can shoot 45 long colt.
For the .44 to be on the list and the .454 not make the list is silly. And why put 2 45-70 revolvers on the list when BFR makes other rifle cartrige shooting revolvers.
I fired a .460, I think, the other day. A monstrous hand cannon. There's youtube videos floating about somewhere. The muzzle flash was great. So much fun shooting the gun.