Sharpshooters, especially CS, are grossly over done & far too many don't know half as much about the subject as they think they do.
Look up Republican Blues on this site as he is a legitimate expert on the subject.
Showing up at a re-eanctment and declaring yourself to the CO as a Sharpshooter is a mistake; many will take offense, others won't have a clue how to use a Sharpshooter anyway. If you have another option I would suggest it. There are plenty of other options available from clerk, QM, sutler, artificer, blacksmith, farrier, teamster etc. as not every soldier carried a musket.
If you are going to insist on a Sharpshooter impression see if you can find a like minded unit; preferably one that knows the difference between a P56 & a P53. If every man has a brass scope and a leather barrel condom run away from them, very fast. If not and they seem legit start doing some serious research. In the threads below you will find several books that you must avail yourself of if you are going to do a credible impression. Then you had best learn how to shoot, I mean really learn how to shoot with a black powder arm at actual combat ranges. So before you spout about being able to hit a mans head at 400 yards you had best be able to at least put it on the paper at that range. Being able to accurately judge distances, windage and knowing required elevations at such ranges are a necessity. Knowing the weapon is only one aspect, a rather small one all things considered, because a Sharpshooter had to be very physical as he was typically working as a scout or skirmisher often very close to enemy lines.
Below are a few threads that might garner some knowledge.
http://civilwartalk.com/threads/sharpeshooter-in-reenactments.21940/
http://civilwartalk.com/threads/confederate-sharpshooters-rifles.94018/
http://civilwartalk.com/threads/what-did-it-take-to-be-a-confederate-sharpshooter.81107/
http://civilwartalk.com/threads/soldier-marksmanship.78681/
http://civilwartalk.com/threads/sharpshooter-doctrine-and-ranges.77520/
http://civilwartalk.com/threads/weapons-of-the-confederate-sharpshooter.74209/
http://civilwartalk.com/threads/longest-sniper-hit.16731/
http://civilwartalk.com/forums/impressions-of-the-civil-war.140/
http://georgiasharpshooters.org/
IMO if you are going to do an impression; do the best you can or don't bother.