From Civil War Artillery.
A.M. DeBree joined the U.S. Navy in 1841 and the Confederate Navy August 1862. Stationed at Tredegar as assistant inspector of ordnance 1862 to 1 October 1863 , when he became commander of the Richmond Naval Ordnance Works.
He apparently used the initials "A.D.B.", generally prefixed by "P" (Proved).