The M1 helmet is a combat helmet that was used by the U.S. military from World War II until 1985, when it was succeeded by the PASGT helmet. The M1 helmet has become an icon of the US military, with its design inspiring other militaries around the world. History Development At the entry of the United States into World War I, the US military was without a combat helmet; initially US troops arriving in Europe were issued with British Mk I Brodie helmets, and those integrated with French units were given French M15 Adrian helmets. The United States quickly commenced manufacture of a version of the Mk I, designated the M1917, producing some 2,700,000 by the end of hostilities. At that point, the shortcomings of the M1917, which lacked balance and protection of the head from lateral fire, resulted in a project to produce a better helmet which would also have a distinctively American appearance. Between 1919 and 1920, a number of new designs of helmets were tested by the Infantry Board in comparative trials along with the M1917 and helmets of other armies. One of those designs, the Helmet Number 5A, was selected for further study. This was an improved version of the Helmet Number 5, developed in 1917 and 1918 by Bashford Dean, the curator of arms and armor at the Metropolitan Museum of Art, which had been rejected during the war because of its supposed resemblance to the German stahlhelm. Eventually, tests held at Fort Benning between 1924 and 1926 showed that although the 5A offered better side protection than the M1917, it was more easily penetrated from above and in some circumstances the shape of the helmet could interfere with properly holding and firing a rifle. Further ballistic tests at the Aberdeen Proving Ground resulted in the decision to retain the M1917 in 1934, which was then given a redesigned leather cradle and designated the M1917A1 or "Kelly" helmet. In 1940, with World War II raging on in Europe and Asia, it seemed likely that the United States might soon be at war again. The Infantry Board resurrected the quest to find a better type of helmet, since the ongoing conflict had shown that the M1917, designed to protect men standing in trenches from falling shell splinters and shrapnel, would be inadequate on the modern battlefield. The board reported: Accordingly, the board, under the direction of