Question regarding bullet hole in WWII US helmet

[SteveR]

The helmet is a front seam fixed bail early war helmet.
It has been shot with a 22 round. There isnt a pelet gun made that would dent the helmet that way.
Look at the size and the shape of the dent inside.
I am extremely familiar with modern fire
arms and ammo and can guarantee it is a 22. A nine would penetrate it.

[Franz1944]

Agree with stever I think it 22

[davejb]

Either way its not battle damage, therefore post war inflicted

[Wagriff]

Of course, you always have to factor in just how far Away the shot that hit it came from too-it may well have been a nearly spent round. Or then again, it may well have been an idiot with his helmet at home proving a bet that his helmet would have stopped a round from across a football field distance....who can say?