Various US army experiments led to the iconic M1 helmet, adopted at the end of 1941. As a stop gap, old M1917 helmets were refitted with new liners copied straight from the experimental 5A helmet, which would not be adopted. The 1917A1 possessed an improved suspension system made from leather over a sheet metal frame. By 1940, McCord Radiator Co. was granted a contract for new M1917A1 helmets as the military expanded and the draft began to overcome the extreme shortfall in manpower to even begin to approach a wartime footing. The M1917A1 was not intended to serve indefinitely. It was retained and even newly manufactured through much of 1941 because it was already in use. When the M1 helmet became available, the ‘17A1’s were quickly phased out in all branches of the US military by the fall of 1942.