"PRIVATE ABRAM C. ACKERMAN Residence: Sudbury, Rutland Co., VT
TWELFTH REGIMENT, COMPANY G. Date of enlistment: Aug. 18, 1862 Date of muster: Oct. 4, 1862 Remarks: Mustered out July 14, 1863. Military engagements: ~Fairfax Court House, Va. [Repulse of Stuart's Raid], Dec. 28, 1862. ~Companies B and G, Gettysburg, Pa., July 3, 1863. Check out http://www.vermontcivilwar.orghttp://www.vermontcivilwar.org for more details.
Source is "Roster of Vermonters who served in the CIVIL WAR", prepared and republished under the direction of Martha T. Rainville, The Adjutant General, Vol. 2, Camp Johnson, Colchester, Vermont, 1998, pages 456, 457, 469, and 470.
Sorry, I don't know whether or not this is your ancestor.This is just material I have on hand. Jan