Roundballs with a buttered .105-018 cotton patch pushed by around 70-80 grains is a good starting point.
You can also do a google.com search for 240 grain PA Conicals by Hornady. Try around 70-80 grains with those. If you cannot find them, go to Hornady.com. Many bullet reloading aisles in gun stores carry them in the Hornady bullet section.