Over 25 years ago, I was deer hunting in minus 30 temps. Went to take a shot at a nice buck, drew the cock back fro 1/2 to full, and the main spring snapped. I had fired that rifle at least a 1000 times without a hitch, but when I got home I could see a tiny bubble/void in the spring casting. Luckily it was just on my property, so not a lot of travel involved, but I carry spare springs now.