There was a big debate some months ago on the security blogs about bullet-proof designer clothes, which started a thread on whether helmets could stop bullets effectively.
I guess the answer is a definite yes, if you include the ability to deflect force and protect the user against harm.
This harrowing story from Iraq suggests that the troops find the latest technology in helmets heavy and cumbersome, but that it undeniably lowers their vulnerability. Although I understand that the story is meant in part to reassure soldiers to keep their lid on, I couldnt’ help but notice there is no mention whether the prior helmet model would have failed or done a similar job:
The round, most likely a 7.62 mm from a sniper rifle, ricocheted off the upper left side of the helmet, shredding the outside and slightly cracking the inside.
I’ll take two.