1949년 미육군은 6×6대의 전술 트럭을 탑재한 오프로드 하중 등급의 10톤(9,072kg)의 추가 중장비 가족을 위한 요건을 설정했다. 맥’s design, influenced by their WWII era NO, was chosen. Designed as an entire family, only the semi-tractor and cargo/prime mover were built. 392 M123s were built between 1955 and 1957 and 552 M125s in 1957 and 1958.
In 1965 CONDEC began building 3188 diesel powered M123As, Mack began building 420 in 1968. In 1969 Mack then upgraded 210 gas engine models to diesel power.
With the Army using more self‑propelled artillery, the need for prime movers was reduced, no follow‑up orders for M125s were made.
Both M123s and M125s saw service in the Vietnam War. M123 tractors remained in Army service into the 1990s.
소스: 맥 M123 트럭 에 위키백과