Start selling some dumb shit, like trump diapers, a trump doll that says "grab em by the pussy" or some other dumb ass shit his base likes. They'd snatch that shit up in a heartbeat. Take some of the proceeds for yourself, set up an account to put some into to donate to blue causes and candidates, and rinse/repeat. I guarantee that's what many of them are doing now. (Aside from the donate to blue part of course)
I mean, trump sneakers, trump bibles, trump watches, trump coins, trump assassination sneakers, you can't make this shit up.
It would be fine to engrave the cases, but not the bullets. It would change the balance and aerodynamics, making them highly inaccurate, and that is dangerous and highly unethical.
Now if you wanted to make them underpowered or duds, I suppose there's an argument for that. You'd have to reload them yourself though, and it's possible you could be held liable.