Could your average dip-shit tranny clamp down a cartridge and engrave something on a curved brass surface? More likely someone else did it and handed off the ammo. I'm guessing the gun too. This was a premeditated killing by more than one person.

I wouldn’t engrave a projectile I wanted to fly true for 200 yards.

Probably just used a sharpy.

That would be like aircraft crews putting graffiti/messages on the plane instead of on the bomb.

But we know these people are stupid...