In November of 1950, the US Ordnance Department requested an improved version of the Browning 1919 air cooled machine gun for use in tanks. The new version was to be able to feed from either the left or right, a feature which was unimportant for an infantry gun but much more relevant when mounting guns into the tight spaces of an armored vehicle. An interim conversion of existing guns to the M1919A4E1 pattern came first, followed by manufacture of all-new guns by the Rock Island Arsenal and Saco-Lowell company from 1955 until 1957.
The design of the gun fell to Bob Hillberg at High Standard. He came up with a clever set of reversible plugs to change the bolt between left and right hand feed, as well as a captive recoil spring, manual safety, improved top cover and rear cover latches, and several other strengthened parts. He also incorporated a charging handle extension with integral manual hold open and a link ejection chute that could be mounted to either side of the gun. His T153 design was formally adopted as the M37, in caliber .30-06. A 7.62mm NATO version (the M37E1) followed as well. The M37 would serve into the late 1960s on the M48 and M60 tanks as well as several helicopters.