Thankfully, the iPhone had some protection in the form of the bullet-proof Marudai case, otherwise it wouldn't have stood a chance. The result after the shot? Well, the iPhone, inside its gigantic, armored case, flied a few meters away, almost falling off a cliff. Unfortunately, although the delicate glass body of the phone was intact, it still didn't want to power on, but it's not known if this was due to the impact from the shot or to its little journey to the edge of the cliff after that.
Finally, RatedRR confirmed that the Marudai case, which, by the way, sells for the whooping $665, managed to stop the .50 caliber round, although, due to some strange consequences, the iPhone itself did not really survive.
If someone's interested in this kind of extreme protection for their iPhone, they can check Marudai's website, where they can learn more about the bulletproof case or simply order it.