Re: Your Help required please
What is funny is that the Sumi, Laplanders etc. who live there year round mostly use military surplus rifles in 6.5 x 55 Swede as there hunting and protection rifle.
Our camp is in a polar bear migratory route and the camp ground is protected with a signal wire that sends a charge to the bear and sends a signal to the camp. The cookhouse has a 12 gauge loaded with 2 slugs and a 000 buckshot, and 2 Marlin Lever Guns one in .41 Mag and the other in .45/70. We can't have handguns in Canada for hunting or protection in the wild.
We have a half dozen single shot 12 gauges around the camp all loaded with "banger" shells that shoot an exploding sound charge to scare the bears away. Get into big trouble if you kill them unless they charge or attack then you can kill them.
My personal guns are both Westley Richards bolt guns the first in .425 WR which is never out of my hands when I'm out of doors and close at hand indoors and the other is in .318 WR which I feel is adequate but prefer definite so I carry the .425. I have it loaded with a soft nosed (chambered) followed by two solids and then another soft. I have never had to shoot a polar bear, came close so many times but they luckily backed off at the last minute. My partner is buying a used Z-Hat lever gun based on the 1895 Winchester chambered in .375 Scoville-Hawk as his personal carry rifle. Have heard very good things about the cartridge and also about the .411 Hawk although the butt looks very scary for recoil. I'd put a good pad on before anything.
The most we ever had around camp were 7 bears at one time and 25 over the fishing/hunting season. You shoot the bangers and they go away but come back 4,5 even 7 times before they get the idea they aren't wanted or invited to dinner.
The polar bear is the only known bear that will deliberately stalk a human. They are fantastic hunters, can smell a freshly dead fish miles away, are powerful beyond belief, have paws that can be 16" wide and they are the most effective stalkers I've ever seen. All white but disappear in a field of green. You see them stalking lemmings or ptarmigan and they look like huge cats.
Be very, very careful and vigilant and make sure you have a signal wire setup around your campsite. Small ones that would cover about 20' to a side and have on each corner has a banger and flare are available. Set it up before doing anything else.
The Inuit (Eskimo) say to shoot a charging bear in the nose to stop him. Behind the ear is the safest immediate kill.
This hasn't answered your question about caliber but I hope this helped some, Best wishes for a safe and uneventful trek.
There is a certain type of mentality that thinks
if you make certain inanimate objects illegal
their criminal misuse will disappear!