Editing M1 helmet (section)

=== Development ===
[[file:American Helmet Model No. 5 MET DP701191.jpg|thumb|left|The Helmet Model Number 5, intended to replace the M1917 but not adopted]]

At the [[American entry into World War I|entry of the United States into World War I]] in 1917, the U.S. military did not have a combat helmet; initially, [[American Expeditionary Forces]] personnel were issued [[Brodie helmet|British Mk l helmet]]s, while those integrated with French units were issued French M15 [[Adrian helmet]]s. American production quickly began of an American variant of the Mk I, the [[Brodie helmet#United States|M1917 helmet]], with some 2,700,000 units produced by the end of the war.<ref>Brayley 2008, p. 112</ref> 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 Model Number 5A, was selected for further study.<ref name="Studler1941_p.931">Studler 1941, p. 931</ref> This was an improved version of the Helmet Model Number 5, developed in 1917 and 1918 by [[Bashford Dean]], the curator of arms and armor at the [[Metropolitan Museum of Art]],<ref>{{cite web |url=https://www.metmuseum.org/art/collection/search/35957 |title=American Helmet Model No. 5 |author=<!--Not stated--> |website=www.metmuseum.org |publisher=The Metropolitan Museum of Art |access-date=18 September 2020}}</ref> which had been rejected during the war because of its supposed resemblance to the German ''[[Stahlhelm]]''.<ref>Dean 1920, p. 216</ref> Eventually, tests held at [[Fort Benning]] between 1924 and 1926 showed that although the Helmet Model Number 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,<ref name="Studler1941_p.931" /> which was then given a redesigned leather cradle and designated the M1917A1<ref>Brayley 2008, p. 114</ref> or "Kelly" helmet.<ref name="M1917 A1 Helmets">{{cite web|title=M1917 A1 Helmets|url=http://www.usmilitariaforum.com/forums/index.php?/topic/35808-m1917a1-helmets/|publisher=US Militaria Forum|access-date=July 12, 2016}}</ref>

In 1940, with [[World War II]] raging in Europe and Asia for a year and the [[United Kingdom]] seeking help from North America, it seemed increasingly likely that the United States would be dragged out of [[United States non-interventionism|non-interventionism]] and into another war. 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:

{{Blockquote|Research indicates that the ideal shaped helmet is one with a dome-shaped top and generally following the contour of the head, allowing sufficient uniform headspace for indentations, extending down in the front to cover the forehead without impairing necessary vision, extending down on the sides as far as possible without interfering with the use of the rifle or other weapons, extending down the back of the head as far as possible without permitting the back of the neck to push the helmet forward on the head when the wearer assumes the prone position, to have the frontal plate visor and to have the sides and rear slightly flanged outward to cause rain to clear the collar opening.<ref>Studler 1941, p. 933</ref>}}

Accordingly, the board, under the direction of Brigadier General [[Courtney Hodges]],<ref>Cleland 1954, p. 25</ref> took the M1917 shell as the basis of the new prototype, trimmed off the brim, and added a visor and skirt-like extensions to protect the back and sides of the wearer's head.<ref>Studler 1941, pp. 933–934</ref> Rejecting the conventional systems of cradles, the new helmet was given a [[Riddell Sports Group|Riddell]] type liner and suspension system, based on the contemporary style of [[football helmet]], with an adjustable strap for the nape of the neck to prevent the helmet from rocking.<ref>Brayley 2008, pp. 117–118</ref> The resulting prototype was designated the TS-3, and the McCord Radiator Company manufactured the first examples from [[Hadfield steel]]. In tests, they were found to be able to resist a [[.45 ACP]] pistol bullet fired at [[point-blank range]], exceeding the initial specification. The TS-3 was given official approval on June 6, 1941, and was designated "Helmet, Steel, M1". Full-scale production commenced almost immediately.<ref>Studler 1941, p. 934</ref>