Normally I would suggest ANY oil is better than NO OIL ... HOWEVER ... years ago took friends of mine from Ohio up moose hunting in Northern Saskatchewan ... it was COLD ... like REALLY REALLY COLD. First day out one of them had a close in shot of a MONSTER BULL ... he pulled trigger ... nothing happened .. he was devastated... claimed his rifle was always "well oiled and greased". I took the rifle (bolt action) and hosed all the action (specifically the bolt/firing pin) with gasoline from the slip tank in the 1/2 ton to remove ALL THE WELL INTENTIONED gun oil/grease that had totally solidified the firing pin within the bolt. The next day my local Canuck hunting buddies got a bull, cow and yearling calf between us ... my Win 88 .308 performed PERFECTLY despite the -30 conditions because all the Canucks were using well polished and NON oiled/greased guns.