Originally Posted by
LarrBeard
We are just such endless founts of arcane knowledge around here.
For those reading along, black powder is graded by grain size. Black powder for cannons is generally #1, the next finer grade is Fg, followed by FFg (generally considered as a rifle powder) and FFFg, pistol powder.
Since I was overcome with curiosity (it's winter and its too dern cold to get out of the house), I found a 35mm film can and I filled it with FFFg black powder to get an idea of just how many grains would be in a film cannister.
Drum roll ... a film cannister is about 475 grains of FFFg. I would guess that #1 or even Fg would not pack as tightly - be less dense- so guess 425 or 400 grains to a cannister and a cannister and a half of cannon powder would be about 600 grains (plus or minus, your results may vary).
Doing a little arithmetic - with a cast iron ball, you would have a 3-pounder!