The American M55 Self Propelled Gun was developed to replace the M43 and had a design that would be used in future SPG’s, that is a fully enclosed turret to protect the crew that was able too traverse, though limited with the M55.
The turret was mounted on a modified M47 Patton Tank chassis. The rear of the turret could be opened to form a platform to increase the crews working space and could be used to replenish the ammo-storage, which could carry 10 rounds.
Produced by the Pacific Car and Foundry Co. it had been a parallel development with the M53 but instead used a 203mm main gun instead of the M53’s 155mm.
It was accepted into US Army and USMC service in 1952 and its numbers increased after 1956 as all M53 started to be rebuilt into M55’s, which took several years. The vehicle was used during the Vietnam War and started to be replaced during the 1960’s by the M110. It was also operated by Belgium and Italy.
The American M55 Self Propelled Gun Spec’s
Main Gun: 203mm & x1 .50 cal MG
Armour: 15mm steel
Dimensions: Length 7.9m, Width 3.58m, Height 3.55m
Weight: 40.8 metric tonne
Engine: 704hp Continental V-12
Top Road Speed: 48km/h