Pick up a copy of Foxfire 5, it discusses the developement of the flintlock rifle in America and also the making of black powder...

Many folks don't know this but the oldest Company on the New York Stock Exchange is DuPont, founded in 1836 by a Frenchman by that name...
He started making and selling black powder and I have read that David Crockett bought a few pounds and ended up in the Alamo with it...

btw...The 2nd oldest Company is Deere & Company, founded in 1836 by a blacksmith named John Deere who was bankrupt, left his family in New Hampshire and developed the steel plow (instead of iron) which cut through the sticky, black mid-west soil in Illinois...

As mentioned black powder was made in America before the American Revolution, but the quality of other countries powder was considered better...

The basic elements of black powder are about 75% potassium nitrate, 15% charcoal and 10% sulfer...As mentioned, it's the mixing and sizing that is dangerous...It's easier to buy it...

Also...Most agree the Chinese developed black powder about a thousand years ago and if my memory is correct it was about 1200AD before the Europeans learned of it and 1300 before crude hand cannons came about...