https://youtu.be/LbjpIP5ShH0
But something I hadn't expected was a frozen hammer (20:30 in the video), pull trigger, sear drops, but hammer is held in place _only_ by frozen water. With the mag release and op-rod frozen he can't get the round out either, meaning the rifle will fire the round as soon as the hammer thaws out. At that point I would probably be pissing on the op-rod while avoiding getting any into the trigger group

Also interesting that even if you can disengage the safety on a hot rifle, if you run it dry so the bolt locks open, and you can get the mag out, you might struggle to get the bolt to drop on a fresh mag anyway. I was very surprised that none of the AR platforms seemed to allow water into the bolt to freeze the firing pin solid, or perhaps the hammer strikes it hard enough that it's not an issue.
I have never seen snow, except from about 5km away, and have never experienced temperatures much lower than about -2C.
Any of you experienced firearm issues related to freezing conditions?