Basically all guns run a risk of breaking in the winter time when temps drop below zero.
Running stock just helps minimize your chances of cracking a mechbox from the piston impact everytime you shoot. Try not to run full auto on your shots and typically your okay to -10 or -15, if your running mini batteries get a few spares as they will drain considerably faster in the cold, and keep your spares under your gear close to your body for warmth.
Saskatchewan Age Verifier! Contact for more Info.
http://airsoftcanada.com/showthread.php?t=174161 - Honour & Respect your fellow players! #Airsofthonourandrespect