The Institute of Heraldry Web site does not list the approval date for the 320th Field Artillery Regiment, 4th Battalion oval, or Airborne background trimming. But since all the approval dates for the ovals worn by the Regiment’s other Battalions all fall after they were designated as a numbered Battalion rather than a Battery and while assigned to an Airborne-designated organization, it is likely some time after the unit was redesignated from Battery D, 320th Field Artillery to HQ and HQ Battalion, 320th Field Artillery in 2004.
Ovals are worn by personnel in an Airborne-designated unit or organization who have earned a Parachutist or Air Assault badge, with the main portion of the badge—i.e., ignoring the star and wreathed star found on the top of Senior and Master Parachutist Badge—centered on the embroidered oval before the combo is placed on an authorized uniform component. In the most recently published regulations (January 2021), these include the coat of Service Uniforms (AGSU and ASU, including the ASU Dress variation), the shirt of the Class B ASU, and the blue or green Army Maternity Tunic (female Soldiers only).
General wear guidance for ovals is found in
subsection (b) of Chapter 21-32 of DA PAM 670-1. The regulations regarding the wear and positioning of the oval-backed Parachutist and Air Assault badges are more complicated and are found in
subsection (b) of Chapter 22-16 of the same manual.
The 4th Battalion, 320th Field Artillery Regiment was originally constituted at the same time as the other Battalions of the 320th Field Artillery Regiment as Battery D, 320th Field Artillery, an element of the 82nd Division and like them fought in three campaigns during World War I. It is also credited with taking part in six campaigns during World War II, but that action came while it was part of Battery A (later the 1st Battalion): it was absorbed into the unit on 13 February 1942, and consequently is credited with the same campaigns and military decorations as 1st Battalion, 320th Field Artillery Regiment.
Following World War II, the former Battery D, 320th Field Artillery was reconstituted on 22 March 1957 in the Regular Army under the same title and assigned to the 82nd Airborne Division on 1 September 1957. But the Battery would not see combat during the nearly seven years it was part of the Division, which ended with it being relieved from the assignment and inactivated. It was reactivated in October 1986 in the Panama Canal Zone and assigned to the 193rd Infantry Brigade, where it took part in Operation Just Cause in 1989.
Its assignment to the 193rd Infantry Division ended with its inactivation in 1994, followed a decade later by its final assignment to the 4th Brigade Combat Team, 101st Airborne Division and then its final designation as 4th Battalion, 320th Field Artillery Regiment on 1 October 2005. Over the next ten years, it would be deployed in support of Operations Iraqi Freedom and Enduring Freedom four times, once to Iraq and three times to Afghanistan.
In 2015, as part of the Army’s downsizing mandated by the 2014 National Defense Authorization Act, the 4th Brigade Combat Team and its components were inactivated, with a ceremony to recognize the history and achievements of 4th Battalion, 320th Field Artillery held on 22 April 2015.