[The weapon vendors may not mind an underage kid buying their wares, but guess who does mind? The police! Hijikata takes notice of Homura exiting a gun shop with a brand new firearm case during one of his patrols. The normal thing to do would be to confront her right away, but instead he first takes a phone photo of the shop to remember it and return to admonish the owner and salespeople later, then follows her at a distance while radio-calling his partner.]

Dojima? I have an underage girl here who just bought a gun like it's cotton candy. Can you come over? I'm shit with kids, so I'll leave the confiscation to you while I give the shop people a talking-to.

[Honestly, while he is bad with kids he mainly wants Dojima to handle the interaction with Homura because he gets a sense of intense disdain from her that he'd like to avoid if at all possible. I think this kid hates me.]