Full disclosure: I'm 56 years old, and still own a Lee-Enfield that was given to me by my father when I was 13, which originally belonged to HIS father. It still works as well as it did the day I got it.
I grew up in Labrador, hunting fishing and camping. I had two tours of CFS Alert, at 82 deg 30 min North. I've been to Whitehorse, Yellowknife, Churchill, Tuktoyuktuk, Iqualiuit, and very many places in between. Believe me, I've seen cold - but cold isn't even the biggest problem.
The Rangers are generally either Innu or Amerind. Technically, they are on duty or on call 24/7. Most of those involved in the Rangers still follow their traditional lifestyles - they hunt, fish, and trap for a living, and spend their time outdoors.
They don''t carry multiple weapons - they don't have the space or weight to spare, given the rest of their kit. That's why the Lee-Enfield has lasted as long as it has - it can be used to hunt for seal, moose or caribou, or defence against moose (ugly, nasty brutes - very evil tempered), wolves, or polar bears. You can hit a target out to about 350 yards or so - more than sufficient for any practical use, and long enough that you don't have to do extra laundry because a polar bear decided that you looked like a snack.
In the meantime - the rifle is carried around on your back while you're going through thick brush, getting banged and nicked as you go. It's sitting in the bottom of a canoe, or a kayak. it's getting banged around while sitting on the running boards of the snowmobile. It's in the bottom of a 12 foot motor boat while you go from island to island in the Arctic Ocean, getting banged around and covered with salt spray. It's stuffed where ever it can fit on the dogsled (yes, they are still used in some places). And after all that crap and abuse, you just have to pick the thing up, and it will hit what you aim at. No fuss, no muss.
Bottom line: Stand me in the world's best gun shop, give me unlimited credit, and tell me I can take one - and ONLY one weapon. I'll take the Lee-Enfield, every time. And I'll still be using it when every other weapon there has died of old age or just disintegrated because of the environment.
I pity the poor bastard that has to make the decision on the replacement. I'm just glad it's not me.