Discharge of a firearm is illegal in my city, its cruel and I hate doing it but I fill a large garbage can full of water and throw the trap in that.
That is consider illegal here, they have that listed as cruel. Once you get the permit you have to bring it in to be euthanized. That is the only way it's legal. So most people just pay a licensed wildlife person to trap and they legally can relocate. In the end it will cost about the same money wise