Any real life soldiers here?

[SpaceDorf]

Mythbusters put that to rest, they beat the crap out of some c4 while burning and could not detonate it, though, in the end, they both said they wouldn't do it because...superstition for lack of a better word?

Fear, maybe?  That would be my own personal motivation for not wanting to detonate C4 manually.  Real, honest, legitimate I don't want to die fear.

What and forfeit winning a Darwin Award ?
Oh wait .. I was thinking of Jackass.

[ReZpawner]

You are pretty much told not to push your luck when it comes to explosives. I was even asked to drive carefully when driving around some EOD guys....and a shitload of unexploded ordinance in the backseat... Also, there are more than one type of explosives handed out in NATO countries. Just because you got C4 one time, doesn't mean that you won't get some other semtex variant the next time.

It's probably more standardised in the US, but in other countries it appears more random.
Probably a good idea that people don't test it out every time they are making tea.

As for the helmet... you can adjust them a bit, usually enough to fit a toque or balaclava underneath. There are also special earwarmers for them for use in arctic conditions. Some units use helmets, others prefer to go without. It really depends on the situation you're in.

[b0rsuk]

What I didn't see mentioned in this thread: helmets don't protect against direct hits anyway. They are good for riots and low velocity projectiles, and for ricochets and debris. Hell, suppose a helmet was indestructible. If you get hit hard enough, your head will jerk and you will break your neck. Maybe at extreme ranges of a weapon's effectiveness.

A true unbreakable helmet would probably need to be fixed to your shoulders to prevent breaking your neck. We can assume power armor helmets are designed like that.

[Bozobub]

False!  The ECH (Enhanced Combat Helmet) currently in use by the US DOES protect against direct hits, up to .30 cal. (although it might break your neck doing so ).  It looks a lot like the old "K-pot" (PASGT) or its immediate succesor, the "ACH", but is quite different in materials and construction.

[DariusWolfe]

To expand on what Bozobub says, the older model K-pots (kevlar helmets) were also quite effective against direct hits from bullets up to similar calibers; You were getting your bell rung, especially if you didn't have it properly strapped, but most of the bullets used on the battlefield weren't going into your brain, and neither was most shrapnel, and the velocity of most shots aren't going to break your neck either, unless you get hit just right.

I'll also graciously accept the correction, as I did speak incorrectly on nomenclature; ECH is the new-new helmet, ACH is the old-new helmet.