There is an awful lot....
... I don't know having to do with the forces that accelerate the bullet and move it toward the target. That includes things that happen outside the barrel when the bullet is just one or two inches past the muzzle.
With several of my revolvers I can get more speed by increasing the powder charge but when I go beyond a certain point, accuracy declines. I think that phenomenon is fairly universal.
I think that has to do with powder outside of the barrel continuing to ignite creating forces that are not confined by the barrel. Consequently these forces are far less predictable in the acceleration they impart to the bullet.
I have never read this. I have never done any scientific inquiry. I have never had anyone verify that it is true, but it certainly seems to work this way.
I would be happy to have someone who knows, tell me I am right or wrong.
My reading of history convinces me that most bad government results from too much government. Thomas Jefferson