I believe the gun with the longest in-service life is the Browning M2 .50 cal “Ma Deuce” that hits its 100 years in service this year and is likely to continue into the future.
You would be mistaken. Reading the article before commenting is an interesting concept!
I recall another Canadian Ranger happening several years ago involving Americans winter overlanding. Two highly prepared trucks set out to travel the Alaskan Highway north then onto an ice road to a small village on the Arctic Ocean. The AK highway was was closed down by a blizzard then reopened so they continued north. It turned out the gate was only briefly open before closing again because another storm brewed up. Their trucks were the only vehicles on a 100+ mile stretch of road.
A Ranger was worried about their safety and headed into the storm to check on them. The American were fine, hunkered down with their trucks when he caught up. While everyone was talking, the Ranger (who was carrying his rifle) told them to look closely at a nearby ridge line. They saw several wolves sitting, watching. The Ranger told them the wolves were stalking them for dinner. And that's why they really valued the reliability of the reliability of the Lee Enfield.
The Lee Enfield was their standard rifle since WW1 and never replaced because of reliability. It worked at -40F, had adequate accuracy and stopping power including moose, bear and wolf. I understand it's been completely retired now but don't know what the replacement is. Maintenance issues finally became too burdensome. They were plum worn out.