Gules, a bend Or between an oak leaf and a rock Argent.
That for the regiments and separate battalions of the Army Reserve: On a wreath of the colors Or and Gules, the Lexington Minute Man Proper. The statue of the Minute Man, Captain John Parker (H.H. Kitson, sculptor), stands on the Common in Lexington, Massachusetts.
TIENS TON CANON (Hold To Your Gun).
The shield is red for Artillery. The bend is from the arms of Lorraine. The red of the shield and the gold of the ordinary are the tinctures of the Artillery units and also of the arms of Lorraine, the tinctures of the latter being reversed. The oak leaf is for the Meuse-Argonne operation and the rock is from the arms of St. Mihiel, the charges representing service in France during World War I.
The crest is that of the U.S. Army Reserve.
The coat of arms was originally approved for the 307th Field Artillery Regiment, Organized Reserves on 25 June 1928. It was redesignated for the 307th Field Artillery Battalion on 10 August 1942. The insignia was redesignated for the 78th Regiment, Army Reserve on 24 January 1962.