Production of the U.S. Army M5 antitank gun began in December 1942, and in November 1943 a slightly modified carriage was standardized as M6, replacing a flat shield borrowed from the 105 mm howitzer with a new sloped one. In January 1944, Army Ground Forces requested that guns built with the early M1 carriage be upgraded to the M6 carriage, so most guns that reached the frontline had the M6 carriage. The first towed battalion, the 805th, arrived in Italy in October 1943, and the M5 later saw combat in the Italian Campaign and in Northwest Europe. One of its most notable actions came during the German counterattack on Mortain in August 1944, when the 823rd Tank Destroyer Battalion, attached to the 30th Infantry Division, helped successfully defend Saint Barthelemy by destroying fourteen tanks and a number of other vehicles while losing eleven of its guns. Besides its antitank role, the gun was often used to supplement divisional field artillery or provide direct fire against enemy fortifications, as in a report from the 614th Tank Destroyer Battalion that recorded a two-gun section firing 143 shells at an enemy post and achieving 139 hits. Although the M5 easily outperformed older antitank guns in U.S. service, it was large and heavy, making it hard to move into position, and its antiairmor performance proved somewhat disappointing. An Armor Piercing Discarding Sabot round was never developed for it, and although an Armor Piercing Composite Rigid round existed, it is not clear whether towed Tank Destroyer battalions ever received it. Because of these shortcomings, commanders and troops generally preferred self-propelled tank destroyers, which offered better mobility and better crew protection. A displayed gun at Jeff Davis Post 18 bore "A 160" etched on the inside of the shield plate and, with its low production number of 1979, most likely saw combat operations in Europe during World War Two. During the postwar years, the War Department and Department of the Army made many individual donations to veterans' organizations and museums, but complete provenance for this gun is unavailable because such records were considered temporary and destroyed after their administrative use. Today, the M5/M6 is used by the U.S. Army for ceremonial purposes, and the Presidential Salute Guns Platoon of The Old Guard maintains a battery of ten M5s at Fort Myer for service mainly in the National Capital Region.