The M114 apc was designed in the early 60’s as a light, fast and stealthy recce apc.
Sadly it’s lack of real armour proved to be it’s downfall after it was used in Vietnam where they would be simply blown to pieces!
It was replaced in vietnam by the M551 Sheridan light tank.
In an attempt to improves it’s firepower it was fitted with a 20mm cannon.
It continued in US Army service until the early 70’s.