Punitive is something intended to punish. No law can prevent you from breaking it, it can only establish that there will be a punishment for you if you do. Adding more laws to “prevent” gun violence is flawed on its face because all they can do is punish you for using guns, and there are already laws designed to punish you for killing or injuring or threatening people with guns. No law will prevent someone from getting a gun in a country where they are so abundant, and someone who intends to murder is already well past caring about laws.
I just realized your confusion may have come from a typo in the original post. I said “putative“ when it should’ve been “punitive“.