Beware, I have a blackbelt in Newtonian Physics. I believe the source of this info to be authentic (a book on wwii air combat by somebody that was there.) Yes the bullets would lose energy when they hit the ground. How much depends on several factors mostly affecting the elasticity of the ground (packed earth, concrete, pavement or stone, moisture content, temperature--below freezing? etc.) and the bullets. I would think the bullets would be lead, but if they happened to be steel, this is a very elastic material. The bullets would be packing quite a punch before they hit the ground so they could afford to lose some. Because sometimes soldiers were bruised by ricochets doesn't mean that at other times they weren't killed. I know of someone who was killed by an accidental ricochet from a hunting rifle off a steel granary (my father actually knew him and I believe my father, a very honest man--the bullet would be lead in this case.)
Crash Orange, just to blow my credibility completely out of the water, there was an incident where a mortar operator saw a tank coming down the road he was beside into a valley with his hatch open, so he did the most reasonable thing and lobbed a mortar round into it.
Speaking of aimbots, there was a Canadian who is famous for encountering a German tank coming down a road with ten or so soldiers riding on it. He was hiding in the ditch and was in a heck of a predicament because they would surely discover him as they drove past. Luckily he had at hand: 1. a machine gun, 2. an anti tank gun. You know what comes next.
