Originally Posted by
sabotloader
The chemical make-up of BH 209 includes both Potassium and Sulphur. Given enough time and moisture it will rust your bore.
Adding those two extra BP ingredients and the equivalent volume measure was the only way General Dymanics could get their smokeless/progressive burning powder listed as BP sub.
With all of that it is a great powder by overpriced.
I can assure you, in 10 days of hunting in Colorado there's no sign of any rust in my Ultralite. I've left BH209 in my gun for the full two weeks of Buck season in PA with no signs of rust. I've never even come close to seeing any kind of rust on stainless Muzzleloader's. I also used to load 777 in my Encore for a week of hunting and never seen rust. So will it rust, I'm sure in time ecspecialy if you don't take care of your ML and don't use a good preservative in your barrel. But nothing I ever need to worry about and most shouldn't either ecspecialy with BH209