Check out this photo. Finally had some success.
I went out at about 7 a.m. instead of 4:30 p.m. There was more activity, and the squirrels seemed less spooky. I chased a whole bunch. Fired 4 shots. Killed one. I think the scope is zeroed too high for 50-foot shots, and it's tough, aiming at something that jumps around like a crackhead.
The .17 HMR is fun, but I miss out on shots because they're too horizontal. I don't want to shoot a rifle unless it's nearly straight up, to avoid problems with the neighbors, and I keep trying for head shots to avoid ripping the squirrels up. I think an air rifle is in my future. I went out with the 16 gauge later, but I saw absolutely nothing.
I was surprised at how stupid the squirrels were. I shot one, and then I walked a hundred feet and saw 2 more screwing around in a tree. I saw a bunch of them, right after shooting the first one. They don't seem to care.
I used Peltor earmuffs. Really neat. I turned them up so I could hear better than normal.
I plan to go get some bigger shot for the 16 gauge. Right now all I have is 8. Thanks for the help.