I have used those lttle packets of synthetic break grease on my AK rails and it has worked great. I normaly use Tetra lube grease on my handgun slides and barrels. They have been shot in winter and summer in Northern and Southern Utah with no problem. Rem oil is another type I use on some pistol parts and .22lr. If I was going to be in sub zero weather and knew it I would probably look into some dry film lubricant.