I'd keep my hand cannon purely because I want to master it and its a big grin on the firing line. For myself a .22 semi such as a Ruger Mk2 would be the ideal, light weight low recoil and adequate for 25m targets.
Airpistol is good at 6m or 10m but can be a struggle out to 25 or 50m.
“If a cricketer, for instance, suddenly decided to go into a school and batter a lot of people to death with a cricket bat, which he could do very easily, I mean, are you going to ban cricket bats?” :- Prince Philip said after Dunblane