You have all the strength you need. I shoot Sharps rifles and make paper patch bullets. For my heavy hunting loads I use Hodgdon Varget and AA 2495 and I can get 1800 fps in my 45-90 and 500 grain bullets with pressures in the 30,000 psi range according to the Hodgdon folks. Your 98 Mauser will take that in stride with no sweat. With your 45-70 and 450 grain bullets, 52 grains of Varget will max out the case. AA2495 will go with around 50 grains with slightly heavier bullets You will get all the velocity you want and it will do a good job for you in Alaska. A 400 grain Barnes X should be a great bullet for about anything you want to use it for. If strictly for bear protection, go with a 500. Enjoy your rifle, you have a good one. When I lived there, if I was in Brownie country, I carried my 416 Rem. If only black bears were visitors, I carried a 44 Mag with 300 grain heavy loaded cast bullets. Your Mauser will work in both cases.
Good shooting,
Dave
