I hunt on a clean dry barrel. All oils are removed. I make sure the breech plug is spotless. Therefore, there's no need to fire a primer before loading, and no primer fouling to suck moisture out of the air.

If the weather is dry I will leave the gun loaded, but I don't bring it into a heated area. I leave it in a locked garage. It's going from cold to warm that causes metal to sweat. After a few days I'll push the load out just for peace of mind. I've never seen powder that looked like it would not fire.

If it has been raining, I push the load out after each hunt and reload in the AM. I shoot FPBs and can re-use the bullets. I also try to catch the powder and keep it in a separate container for practice. It seems to go off fine.