.300 or .338 would both be excellent for hunting Alaska but in my opinion so would the 7MM Ultra mag which Joe already owns. The Ultra mag has 13% more powder capacity than a.300 Weatherby and 20% more than a .300 Win.. Team that up with a 175 grain Nosler Partition at over 3,000 f.p.s. - get the picture. It used to be few bullets could hold together at these velocities but with the new bonded bullets you can have speed and penetration. In my hunting experience several big game animals have been killed instantly dead with heart lung shots at close range with 3,000 f.p.s. impact velocity, hydrostatic shock. When in high school I worked in a butcher shop where we processed animals culled from the national bison range, mostly bison but deer and elk also. The shooters gun of choice was a 220 Swift, he could have used anything he wanted but this gun efficiently got the job done at field ranges. Todays gun scribes would have you believe a cannon was needed to dispatch an animal the size of a bison. Once a friend shootin 30-06 with accelerator ammo - 22 caliber hollowpoint in sabbot at over 4,000 fps penetrated a piece of 3/8" plate steel with a nice round hole while my 300 Win. put a large pock mark but did not penetrate, we were shooting at about 25 yards. Speed, heat, boring action, why would this blow up bullet penetrate plate steel? I guess my point would be to not under estimate the effects of high velocity. Once while visiting outfitter Billie Stockton in Wise River Jim Zumbo was there and was writing an article on cartridges for hunting elk. We talked about killing elk and he said he was just filling the pages, more bullshit.