I’ve been thinking about Gettysburg recently, and I think the outcome would have been different if the South’s gigantic artillary barrage (loudest sound ever in North America up til that time?) would have been more effective. They overshot their targets and so didn’t “soften up” the North at all.
Do you know much about the Civil War? Was the South just always pretty bad at aiming/shooting their cannons? Or just at Gettysburg?
That said there are many "accidents of war" where somebody never corrected fire as the enemy advanced or mixed up coordinates of artillery fire.