Cartridges of the World..
9th Edition, pp86
250 Barnes 58.9 gr of N200 vel 2,500 3468 ft/lb
350 AWB/FP 66.9 gr of W748 vel 2,226 3853
these are just a few samples in case you're just considering buying and want an idea of the potential. I'd check any of the powder or bullet mfg's sources, Steve's pages, and Accurate reloading website
FWIW...if you haven't bought it yet, you might consider a .45-70 instead (unless this one is a steal or you just want it). With handloads my .45-70 will do about anything the .450 can, but with common (and much cheaper) ammo. Unless they're popular in Alaska, I'd suspect this round will get obscure pretty quick.
Of course, this is coming from a guy with a .357 Herrett and .45-90.
If you want the full write up, check out the COTW book or pm me. HTH