My Grandfather Andrew J. Sawyer served with Company C. First Michigan Sharpshooters. He Enlisted Nov. 12, 1862 at Reading Michigan for 3 years at age of 18, Mustered into service March 31 1863 and Mustered out at Delaney House Washington DC. July 28 1865.
Here is Andrews Discharge paper. click on the Image to enlarge it.