I can recommend the book: "Civil War Guns" by the late William B. Edwards. The book is highly readable and if you have an interest in Civil War guns, it is hard to put down the book.
http://www.amazon.com/Civil-War-Guns.../dp/1577470230
I knew Bill Edwards and he was the consummate historian. I recall on on visit to his home in Afton, Virginia (many, many years ago) I questioned a statement he had made in his book about Sharps Carbines. He led me into a room that literally had banks of filing cabinets, went to one of the cabinets, opened a drawer and then flipped through manila folders until he found the one he wanted.
He brought the folder to me, opened up and showed me the original documents on which he had written what he did on that subject! I never again questioned his accuracy. Historians since him have done more research and brought to light more facts and details...but Bill was one of the first authors to write a very readable book that never will really get "out of date."