RE: New heng Long 1 16 rc tanks
You're think about the M-3 TD with the 3 inch gun. It was not a very effective design and they did not fare well except in one campaign in Africa. The 3 inch giun (75,777mm) was an outmoded M-1918 anti aircraft gun and the weight of the gun caused many of them to tip over on some hills. The gun had to be within 20 degrees L or R of the target to engage which made maneuvering in combat very difficult. It was OK as an ambush vehicle, but that was not it's intended design.