Assuming it's a serious question, I would venture a guess that it had to do with getting the maximum efficiency and velocity from a (then) fairly slow burning powder charge. I would assume that they did a bunch of testing and found it would take a certain length of barrel to get to that velocity for accuracy at any longer range.
Today, I would assume most black powder rifles are built more period correct, than trying to get a shorter barrel.
Of course they did have black powder pistols also.
Today, I would assume most black powder rifles are built more period correct, than trying to get a shorter barrel.
Of course they did have black powder pistols also.
