Developed as a replacement for the M1941 load carrying system, the experimental Marine Corps XM1964 equipment evolved into the nylon USMC M-1967 field gear. The XM1964 nylon M-14V pouch was designed to carry two M14 magazines, vertically one behind the other. It had a snap fastener closure and could be attached to the belt via two slide keepers. The Marine Corps Landing Force Development Center also produced a cotton duck version of the M-14V, as well as a horizontal pouch (M-14H) in both cotton and nylon.
The XM1964 gear was tested by the 1st Battalion, 6th Marines at Camp Lejeune (North Carolina) and at Camp Garcia (Puerto Rico) between February and June 1966. Consequently, the snap fastener closure on the vertical ammunition pouch was replaced by a plastic spring catch fastener.1
1. Marine Corps Pack XM1964, Army Field Pack, Combat M1961(Modified) Feasibility Study. (Marine Corps Land Force Development Center 1966)