I use 100 gns by volume with a Barnes 300 grain expander 50 cal. It shoots 1 1/2 at 100 yards. Never tried anything different. In my experience with 209, If you hunt with it and don't shoot it you should pull the breech plug and push your charge out every day and reload each day with a fresh charge, If you do shoot. Clean the barrel before sitting all day hunting. It is the hardest substitute to light and if you are going to rely on it have a fresh charge in a clean barrel. I know because I didn't do the above and had hang fires and failure to fires.
If you just want the ultimate reliability use black powder. It will light if the cap goes off. Just a pain to clean after use.
