Also might sound slightly crazy, but in your boots, wear a plastic bag on each foot.
No really, wear a pair of thick woollen socks, then put a waterproof plastic bag on. Then a pair of thinner socks over that, then your boot.
The plastic bag keeps your inner sock dry incase you get wet, and it also traps air, insulating your foot much more effectively. BUT be prepared for incredibly stinky feet when you take them off. As you will sweat much more than normal. Same goes for a pair of rubber gloves under your combat gloves.
Other than wear more layers to combat the cold. Multiple thinner layers is better than a few thicker layers, due to the trapped air in the layers.
Your worst enemy is the cold and the wet. Especially on exposed areas like hands and feet. Your core, torso, groin, neck and shoulders, can regulate your temperature relatively easily. Your extremities are MUCH more at risk due to the reduced blood flow to them.
Also, try to use mesh or ventilated goggles or glasses, normal ballistic glasses will easily steam up in the cold due to the condensation from your breath. Effectively blinding you, this can happen on your scope lense too. Keep a vizzy cloth or a rag of some sort handy to wipe off your scope eye piece and clear your view. Same goes for any glass device, monocle, binocular or spotting scope, if you breath on it in the cold, it will steam up.
Also if possible, use a different coloured round. Black rounds work the best because of the white terrain, a light coloured round will disappear in flight, if you need to correct your shot placement it will be made much harder.
Hope it helps.
If you guys havent guessed... I love winter sniping
