There is a way to do it with no report, get some 120 conibear traps and a box of the appropriate size, the plastic tubes that the newspaper gives you to put on your mailbox post works great. Put some sardines, fish scraps, canned cat food what ever in the back of the box cut slits in the front of the box to hold the trap springs and in the morning no more feral cat, no gun shot. If you build the box leave the back open and cover with 1/4" or 1/2" wire mesh and it works even better. Obviously this only works where you don't have any pet or farm cats around that you don't want to dispose of. It is quite, efficent and humane. It is unreal how much damage a feral cat can do to wildlife and song birds in just a short time. In Australia the government hires people to hunt them due to the damage they do, there was a TV show on about it a while back, it was amazing how many of them there were there, according to the show some birds are in danger of extinction due to predation by feral cats there. But this eliminates getting a new gun so I guess you should get which ever one you decide on to carry when checking the traps in case the cat had buddies and you get charged by angry cats seeking revenge