“A 12ga is overkill. I’d just get a .25 caliber, high-power air rifle and snipe them for free. I’m sure someone out there would love to roast them up!”
A Wrist Rocket sling shot and 5/8 inch hex nuts (14mm) will do a pretty good job as well. And the ammunition is probably easier to get.
I'm a snap shot wiz with a wrist rocket. Two out of three tossed beer cans. No aiming just muscle memory. Many years of archery as a youth trained the muscles.