The old rain jacket was not really a rain jacket. I had one dated 1978, the tag read parka wet weather cover. Not rain jacket. In the old winter warfare book, it is used to cover your parka when the weather gets warm. to keep your parka dry. Those of us that have worn the old one and Gortex one, will know the difference. The old one was cotton, it allowed you vent. Cotton does not freeze the way gortex does. At -30c, gortex due to its plastic content gets hard, and holds the water. Cotton is natural and folds, allowing the micro crystals to brake. On my Adv Winter Warfare course, the old ranger always said KISS. Rangers use, equipment so old. canvas tents soaked in oil, cotton/wool shirts, boots with no lases.
I have been hunting and fishing wearing, my old clothing. And warmer than, in my new or military kit. To me high tech is not always the best.
On SUEs we have issued US Army and Marines winter clothing. In 92, 2nd Anglo and 3/67, 75th Rangers have come up, with all their kit. We ended up issuing them our parkas ( pat1964).
Yes. Gor is great if it is keep clean, and reasonably maintained. But at arctic weather, you cannot wash, clothes get dirty with oil.
That is why, I still wear my old one to the field. And my last new one is still in the plastic bag.