The American M53 Self Propelled Gun was developed to replace the M40 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 M53.
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 20 rounds.
Produced by the Pacific Car and Foundry Co. it was accepted into US Army and USMC service in 1952. From 1956 all M53 started to be rebuilt into M55 Self Propelled Guns mounting a 203mm main gun, which took several years.
The USMC operated the M53 during the Vietnam War.
The American M53 Self Propelled Gun Spec’s
Main Gun: 155mm & 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