How much do you trust your friend? And would you trust a bulletproof helmet enough to take a shot to the head?
Yeah, probably not.
Well, two friends in Russia decided to do exactly that and then upload the results to the internet.
As you do.
In the video, one of the guys aims a gun at his friend who is wearing a titanium helmet with bullet-proof glass - it's the same type used by Russian military - and then fires.
While the impact of the bullet knocks his head backwards, he appears to be unharmed.
Some commenters online have wondered if the video is in fact a fake or if the guy just fired a blank (which is still quite dangerous).
Either way, these guys need to find better ways to occupy their time.