A Little More History On The M14E2 - M14 Forum B Engineering Development of Rifle, 7 62mm, M14E2 1 Rifle, 7 62mm, M14 and Rifle, 7 62mm, M15 were classified standard on 23 May 1957 The M15 Rifle was the heavy barrel model of the M14 Rifle intended to be used for automatic fire Tests by the Army and the Marine Corps led to the adoption of the M14 Rifle ·with the M2 Bipod and to the obsolescence of the M15 Rifle on 17 December 1959