I'm listening to Gettysburg by Stephen W. Sears and the officers on both sides seem to always exhort their men to "aim low". For instance, General John Gibbon told his 2nd Division infantry: Do...
history.stackexchange.com
"The sights on the Springfield Model 1861 had settings for three distances: 100, 300, and 500 yards. In the civil war, however, many battles were fought at much closer range. According to
Battle Tactics of the Civil War (Paddy Griffith) many were fought inside of 100 yards. At this shorter range, the bullet didn't drop as much as the sights were calibrated for. Worse, it's almost inevitable that at least a few were using an incorrect setting, so their sights were calibrated for the even longer distances. If you were shooting only 50 yards with the sight calibrated for 500, the projectile was going to hit a
lot higher than where you aimed.
Another point to keep in mind is that many of the soldiers were probably accustomed to shooting various hunting arms. A military load used a prescribed amount of powder that was intended (as you can probably guess from the sight calibration) to maintain accuracy out to around 500 yards. Most people hunting at the time almost certainly used considerably less powder to minimize their costs (at the time, hunting wasn't a game to play in the fall; it was a primary source of protein). Most were probably accustomed to compensating for a fairly extreme trajectory, but the military load shot much "flatter".
There is another point that isn't specific to that particular war, but it's probably still significant: shooting high tends to either kill (if you happen to hit somebody in the head) or miss completely. Although missing is obviously undesired, what may be less obvious is that killing generally isn't considered the optimal result either.
It's actually generally preferred that you
wound an enemy rather than kill him. Although it doesn't always happen, if a soldier is wounded there's some chance that one of his comrades will attempt to rescue him and get him back to where his wounds can be tended to by medical personnel (or at least get him out of the line of fire). When/if that happens, you've effectively taken not just one, but
two enemy soldiers out of action (at least temporarily). Although a rescuer might come back into battle later, getting even a few extra enemy soldiers out of the battle at the right times could be decisive if the two sides started the battle almost evenly matched.
Aiming low increases the chances of wounding an enemy rather than killing him (at least immediately)."