Backyard friendly is different to each person and neighbors. Example my neighbors are crazy morons and when they hear even a .177 airgun going off. They call the cops saying someone is shooting a gun. Cops show up at my house 2 times over a stupid. 177. Cal bb gun saying they get call from neighbors that we are shooting guns. If you have cool neighbors than even a big bore going off is considered backyard friendly. So it's hard to say if your gun is backyard friendly without know what kind of neighbors you have.
I've never had neighbors complain about my R5.30.
If I did have "crazy morons" calling the cops for "airgun noise", I'd purchase a pneumatic nail gun and "build things" in the back yard..5 or 6 nails at a time. I think a birdhouse might take 20 or 30 nails. With a visit from the police each time and you explaining it was a nail gun each time, I suspect they'd eventually stop coming..and maybe even ask the neighbors to stop crying wolf.