I'm going to break a kid's airsoft gun.
That seems cruel. Why would you break their toy?
This kid is so damn annoying. I really hate him.
Even if he is annoying, you shouldn't break his toy. He's just a child. Ignore him if he bothers you so much instead of breaking his stuff.
No. I'm gonna see to it that he stops being so obnoxious.
If you're this bothered by him, talk to his parents instead of breaking his toy. Breaking the gun will just make him upset and won't make him change his behavior. Talking to his parents will be more likely to get him to annoy you less.