We are probably more used in seeing US Military Heraldry displaying the Crest on a Wreath directly placed on the Shield. But as I understand the Formal grants from the TIOH acctualy includes a Helmet. On Wikimedia Commons I found the Arms of the 15th Field Artillery Regiment, depicted with Helmet and Mantling.
The Regiment which was organized in 1917, was during World War I assigned to the 2nd Division and committed to heavy fighting. The Five wavy fesses denote the Rivers crossed by the Regiment during the War - Aisne, Marne, Meuse, Moselle and the Rhine.The Canton is from the Arms of the 4th Field Artillery Regiment denoting formation of the 15th by transfer of men from the 4th. The Crest denotes service as Artillery with the 2nd Division during World War I. The Motto translates as "Let’s Go".
The 15th Field Artillery was to serve in Europe again in World War II and later in Korea and Vietnam. Battalions of the Regiment have in recent Years served in Bosnia, in operation Iraqi Freedom and in Afghanistan. Currently two of the 15th’s Battalions (the Regiment at one time fielded a total of 8 Bns) are active the 1st with the 2nd Infantry Division’s 1st Brigade Combat Team in South Korea and the 2nd with the 10th Mountain Division’s 2nd Brigade Combat Team, Fort Drum, NY.