Thing about that is, the bullet would go up, likely hit crosswinds, and be blown off course, so when it's gone high enough to lose its speed, it will fall back down, reaching a similar speed, but you would be incredibly unlucky to be hit by it because it would never come back down in the same place.
That said, you might shoot it, wait, think, f**k this its not coming back down, walk off and then it land on your head.
If you masturbate too much you will have a sore dick and no jizz.