I think that too many people believe in the "myth" of accuracy of a weapon. "The Legendary Sharps", an experimental weapon with experimental ammunition" Quigley Down Under sure helped the modern day myth of the Sharps. Because of the rainbow trajectory of most all muzzle-loading weapons as well as the percussion breech loaders it makes hitting a target, even a man size target, very hard to hit at ranges past 100 yards.
Most Civil War soldiers were not "accomplished rifle shots". If you do not judge the range of your target correctly, even at 150 yards, hitting with a Sharps or a Spencer is going to be a **** shoot. Yes, an accomplished marksman could hit targets at longer ranges but again these were men that knew their weapon and sights and could judge distance. Shooting at unknown distances makes first shot hits very rare. If you are off in your estimate even by 10 yards, you miss.
Too many reenactors feel they are a regular "Daniel Boone" and can hit everything they aim at. At one event a cavalryman armed with a Sharps percussion carbine proceeded to tell me he could hit a 2 foot by 2 foot target at 500 yards every time. When I told him I would bet him $100 that he could not hit it 5 out of 10 times be did not want to put his money where his mouth was but still insisted he could hit it every time. Reenactors should go out and live fire their weapon at a man-size target at different ranges that are unknown to the shooter and see how many first shot hits they get, then measure off the distance.
As to firing all of your ammunition too fast with a Spencer, as has been mentioned, that is where fire control comes into play. Also those armed with Spencers did start carrying more ammunition to take advantage of their rapidity of fire.
There have been all kinds of estimates as to how many shots were fired per casualty of the different wars. One estimate for the Civil War showed over 2500 shots fired per casualty, I am not sure how "they" come up with the number but is does seem that "they", whoever they are, know everything, LOL.
Reliable hits on a target by an individual common soldier of the Civil War was not very good. Most soldiers were not long range marksmen. Where the repeating rifles came into play was with their volume of intense fire at short range, less than 200 yards but more likely less than 100 yards. When you have the so called "Mad Minute" of fire with the Spencer a "wall of lead" can be produced from a regiment armed with them for a few seconds. I still would take the Spencer but given the choice would rather have a Henry rifle.
Bringing the