I'm in the process of making a AR type rifle out of dowel rods, popsicle sticks and some balsa wood. It won't be perfect bit good enough for the elf to have some range fun. I'll use the pile of sand he was buried in as a backstop. I'll make some targets to put in front of it. Maybe a plate rack? I'll see how much time I have.
Maybe some animal crackers as targets, like an old school shooting gallery.
I am slightly disturbed by the lack of hearing and eye protection.
What about a set up where he is prepping a landing zone for Santa?