The breech was of horizontal sliding type, manual; the recoil system hydro-pneumatic. The carriage was of split trail type, equipped with a single equilibrator spring beneath the breech and wheels with pneumatic tires. Organization Despite the performance advantages, it turned out that no branch of the US Army wanted the new gun. The Infantry considered it too large and heavy. The other possible user, the Tank Destroyer Center, preferred more mobile self-propelled weapons. Finally, pressure from the head of Army Ground Forces, Gen. Lesley McNair, resulted in the gun being adopted by the TD Center. McNair's opinion was apparently influenced by the experience of the North African Campaign, where self-propelled guns were found to be hard to conceal. On 31 March 1943, AGF ordered 15 self-propelled tank destroyer battalions to convert to a towed form; eventually, AGF decided that half of the TD battalions should be towed. A towed TD battalion possessed 36 pieces, in three companies of 12. M3 Halftracks were issued as prime movers. The organization from 1 September 1944 authorized M39 Armored Utility Vehicle instead, but these only reached the frontline in spring 1945. Those towed tank destroyer battalions were attached to US Army divisions to improve their anti-tank capabilities. Most often, a complete battalion was attached to an infantry division. In some cases, towed TD battalions were attached to armored or airborne divisions; sometimes, companies of the same battalion were given to different divisions; and sometimes a single division had several TD battalions – including a mix between towed and self-propelled – at once. Combat service In October 1943, the first towed battalion – the 805th – arrived in Italy. Subsequently, the M5 saw combat in the Italian Campaign and in the Northwest Europe. One of the most notable engagements came during the German counterattack on Mortain in August 1944. The 823rd Tank Destroyer Battalion, attached to the 30th Infantry Division, played a key role in the successful defence of Saint Barthelemy, destroying fourteen tanks and a number of other vehicles, though at the price of losing eleven of its guns. In addition to the anti-tank role, the gun was often used to supplement divisional field artillery or to provide direct fire against enemy fortifications (e.g. a combat report from the 614th TD mentioned a two-gun section firing 143 shells at an enemy post, achieving 139 hits). Although the M5 easily outperformed older anti-tank guns in