Their methodology is probably off because it doesn't seem to account for bullets tumbling. Bullets spin and that spin keeps the pointy end forward. If they're

Their methodology is probably off because it doesn't seem to account for bullets tumbling. Bullets spin and that spin keeps the pointy end forward. If they're fired straight up and then fall back down they're going to end up tumbling. That makes their air resistance much higher and therefore much slower. It will also reduce the severity of impact. Instead of getting hit by the pointy end you're probably going to be hit by a bigger surface area.