Yeah, grenades and baseballs are the same size for the same reason: It's about as big a shape as a person can hold and throw far with a lot of accuracy. It was just a happy coincidence that my grandfather was both on a winning Little League team and the Nazis loved pillboxes with tiny holes. He was part of the 14th Armored and could probably land a grenade in a pillbox from a hundred feet away just like throwing someone out at home from left field.