I normally put leftover BP back into the original container, where I have put a few silica gel packs, to be sure it stays super dry. A couple of weeks ago I left the powder in. When I went to use it, it was very hard to move the handle. I dumped out the BP and found it had started to corrode the brass and cast iron. I was surprised. I’ve left smokeless in many times before and never had a problem. I can understand it. BP is corrosive even before it’s been burned. Next time I will be sure to return it to the container. Has anyone else had a similar experience?