The main drawback of any semi auto gas gun is the consistency of the ammo. If your ammo is all over the place with pressures they are not reliable. Think of it as "regulating" in another sense. I've never used my AR on anything more dangerous tha a coyote but the fact is they do work. Again, I can't speak for freezing conditions but maybe I'll dunk it in a tank and toss it in the freezer just to see? I'm curious also.