have you considered blow gun and darts
the rats can't run into a hole if transfixed with a 6" dart shaft
razor bladed darts do kill rats quickly with proper hits
but even marginal hits tend to anchor them quickly
and its not a gun, so they can,t say your endangering anything but vermin
yeah it takes a bit of practice but its really not all that difficult to master
you can even cheat with glue trap pads
https://www.walmart.com/ip/Catchmast...E&gclsrc=aw.ds