Samsung's latest flagship device - the Galaxy S4 - must have went through the same rigorous testing process that Samsung's other devices go through. That being said, I'm pretty sure Samsung never tested to see if its lastest device was bulletproof.
YouTube personality raredrr saw this glaring hole in Samsung's testing regimen and took matters into his own hands with his latest test to see if the S4 can survive being shot with a 50 cal sniper rifle. Short answer - no. Long answer - don't expect the Galaxy S4 to stop incoming bullets.
As a bonus, here's ratedrr shooting the Galaxy S4's main competition - the iPhone 5 - with a 50 cal rifle. It holds up a little better:[h/t: Kotaku]