1. Make sure your flash channel & vent liner are cleared of carbon.
2. Make sure your bullet/sabot combination fits the bore tightly. Too loose a fit will cause cold weather misfires.
3. Check your fired primers. If there's black running up the sides they're not sealing against the plug well enough and some of the fire is leaking away.

Both my sons use n110 and W209 primers in their Savages with no cold weather issues.