Hi Cassie, okies thanks

I thought up this recently , but I think it might be a bit too easy so I will post my one and another riddle which is sort of based on a true story, peculiar mystery during the first war .
Ok my one first,
What has 6 corners, can weigh many tons yet when impacting on the ground from a height is silent?
And the other one is..
During the first world war commanders noticed an alarming number of soldiers dying due to heavy artillery bombardments, so they issued helmets to every solider. After some time the field hospitals reported a five fold increase in the number of cases of head injuries.
Can you account for that significant increase of head injuries?
fin.