First off, headshots aren't special because it's actually harder to not get a headshot. Second, I don't think the normal safety rules apply when you're hunting yukkuris.
I don't know what type of bullet he's using but that hole in Marisa is very small.
Guns seem to completely defeat the point of "hunting" when it comes to yukkuri. 1. Yukkuri are slow. 2. When pregnant, yukkuri are even slower. If the point was to fuck up the marisa by killing it's children,or even if the target was the marisa itself, a baseball bat would be more than necessary for and identical splatter effect. This is a waste of ammunition and time, as you then need to clean the gun. As for the bullet, entry wounds arn't normally big. Judging by the use of a scope, it could be anything from a .22 to a .303.
@This The point is to make the yukkuri wonder what killed it. More psychological damage to them. If they see someone beating on the children they'll rightly blame the person, if they don't know what killed the sproutling they'll blame themselves, rightly, for the death.
Lol, headshot was kinda redundant... but it's still a head sized target. And about the safety, I was wondering if he meant to kill both, or if he meant to kill the child and accidentally killed the parent behind her too.