Gun nut here: Not a Texan and also not really pissed off about this. I also think it probably won't make much of a difference and home-made firearms have been around for well over 100 years so if someone really wants to make one and doesn't care about regulations, they're just going to make one anyways.
Assuming you are just a horrible person: Buy them gympie gympie leaves, toss them in a gift bag, and don't tell them what they are but that their present is in the leaves.
Thanks Obiden.