[L473ncy]

Simple solution would be to go to a farm or summer cottage or something. Somewhere where it's sparsely populated and there's little chance of anyone else seeing you and freaking out.

You could inform your neighbours that you're going to shoot your "pellet gun" at pop cans from 2-3 in the afternoon and not to worry. Tell them you've taken safety precautions, backstops, safety glasses and such. Where's the other problem? Is your backyard visible from the alley? If so I suggest making your fence higher (within city bylaws though). Note that if your neighbours are **those** kind of people it may be illegal in your jurisdiction to discharge an airgun (airsoft and .177 pellet guns) within city limits (city bylaw ending in a fine) and they may call the police.