Read Otto Carius book, Tigers in the Mud. He writes about the men who crewed panzers, the uncomfortable gritty deadly life fighting one and about his own very small physical stature and how in basic training he was always given the MG 42 to carry, because he was the smallest guy in his unit. The WWII panzer crews were smaller in stature to better fit the vehicles they operated: "Otto had been drafted twice before, but sent home as "Not fit for service at present underweight!". But in May 1940, Otto was finally drafted into the 104th Infantry Replacement Battalion. Following training, he volunteered for the Panzer Corps, (in his book Carius suggests his CO pushed him in that direction, because he was really to small for the Infantry): http://en.wikipedia.org/wiki/Otto_Carius