The most of the military explosives aren't going to explode if shot through or set on fire etc. As everyone can probably imagine it would be quite counter productive if this wasn't a case. They have gone through a great trouble to invent explosives that are only going to blow up when they should.
^^^That is indeed interesting. While it is valuable information it must have been very disturbing work compiling all that gruesome information.
Didn't thought about that but make senseI'd guess that's because that's the head/neck are more exposed than the torso when you're leaning over/around cover? If you're looking at an enemy position, you need line of sight to it, while your torso can be safely behind the wall/sandbags/earth.