Civil War incident
The NRA was founded, as a friend pithily put it, "to teach Yankees how to shoot Southerners" -- the critical event being when the Union officer who would found it discovered that not one of his men could hit a barrel-head at moderate distance. (He also discovered that there was no American military manual on shooting, in terms of hitting a mark. The manuals described stance, but not aiming, etc.)
This memoir by an Iowa infantryman illustrates the problem faced. Understand, the Confederate is so close to them they can understand his shout, and a company (about 60 men in practice, probably more here since it was a new regiment) get in two rounds:
"We expected them to take to their heels, but no, not only did they not fly, but one of them flung himself on a white horse, rode directly at us, and when within shooting distance, hopped off his mount and promptly fired. I happened to be in the front rank, and I noticed the bullet as it glanced off the branch of a tree, and rolled harmlessly at my feet. We answered in kind, but it made no further impression than to have the bold rider fling forth, "You may shoot, you — Yankees, but you can’t hit me anyhow." Then spoke up Silas N. Lee (Editor's note) of Nevada, threateningly, "Look out! Look out!", and we fired another volley, but the gay daredevil was off like the wind."
He also details one forgotten risk... they're ordered to empty their muskets by firing them, it was raining and he'd forgotten to remove the tompion that plugged the barrel, and when he fired it split the barrel.