Joe, I should add that the actual combat use of those rifles in the first two companies (Co. E & I) of the 1st U.S.S.S. was during the Peninsula Campaign. They quickly swapped them for the Sharps breechloader as it was accurate, lighter, easy to use and capable of being loaded in any position (no exposure). Second Andrews Sharpshooters also relinquished theirs after Malvern Hills (June 1862) but only because another unit abscounded with their knapsacks (and accoutrements therein). So, at Antietam, only the First Andrews Sharpshooters had them (and not all did) and a handful of Berdan's sharpshooters (there were a few that clung onto them throughout the war).