I live in Wisconsin and I'd agree winters can get brutal. Considering that fact, I still wouldn't want to be on the receiving end of any .380 round even with all my winter warm clothing on. Unless the crook your defending against has on 5 layers of Carhartt and then some I'd say your JHP or FMJ are going to do fine. For "fun" why not go to Goodwill and buy a Carhartt or another heavy material winter top. Cut it up and layer as it would be worn by someone then place it in front of some water jugs. Run your own ballistic test to see what you personally trust.