By the mid-1970s, Chile and Israel were involved in arms dealing together. The two nations started discussing the Israeli-modified M-51 Sherman. It was mechanically and automotively reliable. Second, it had a gun already evaluated in the French AMX-30 MBT which Chile would eventually acquire in the late 1970s. 
 
The M-51s were well-received and successful. They offered more interior room than the T-54/55 series, the lighter M41, M24 and the AMX-30, particularly appreciated in the colder regions in the south where thicker clothing could be worn. 
 
Israel developed a 60 mm Hyper-Velocity Medium Support weapon system. It was decided to use it in the M-50, to be ordered by Chile, and M24 Chaffees already in Chilean service.
 
The M-50/60 was in the front-line, while M-51s played a supporting role. As of the early 21st Century, the last of the Chilean Shermans were retired, with M-51s first, then the M-50/60s. The tank that first saw service in 1942 continued to serve in a useful role for six decades. Not bad!