This is the fourth part of a series of posts seeking to describe and analyze the 7.62mm Lightweight Rifle concept promoted by the Americans, and subsequently adopted by NATO in various forms. This series will cover development from before World War II to the present day, but will focus primarily on the period from 1944-1970, which constitutes the span of time from the Light Rifle’s conception until its end in the United States with the standardization of the M16. This article itself deals with the fully automatic variants of the M1 rifle developed before US focus shifted to the then-new, shorter .30 Light Rifle cartridge that led to the 7.62 NATO caliber. Therefore, all rifles covered in this article were chambered for the standard .30 M2 caliber, and the series of fully automatic M1 derivatives chambered for the .30 Light Rifle experimental round will be covered in a subsequent installment. In more than one way, this is the first “true” installment of the Light Rifle series, as the three preceding articles can be considered prologue material, though that does not reduce the importance of their subjects. My readers should also note that while I consulted a variety of sources to write this article, my narrative heavily relies upon Bruce Canfield’s magnum opus