HuntAway,
I often wished for a little nip for a nightcap in the field. However Uncle Sam frowned on that idea. All we had was chewing tobacco. I should note however that that was not a good night cap. Rather we used it to keep us awake when on an excercise.
I went to the range with the Uncle in Wisconsin once when it was -20. The Browning 50's wouldn't shoot worth a flip; they would fire 2 to 3 rounds and stop. We would clear them and repeat the same process. I understand the Thompson machine gun was the same way in super cold weather. I suspect it had something to do with the fact that the bolt carrier was rectangular in cross section and fit snugly into the square receiver. Our M60's had no such problem on that day.