John...advice from a really old guy that has always harbored a streak of vigilante somewhere deep under his 'follow the rules" usual persona...
If the offending outside light is inside 75 feet range, any old school BB gun will do. The air rifle wins on nearly silent effect.
If the bastard light is outside that range, you'll need to infiltrate under darkness and cover to do the deed. Closer is better, so you can still go with the air rifle. I'd avoid any true firearm...only stupid kids shoot stuff with their BB guns. Leave the real arms to the extra stupid grownups
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It would be almost admitting to a crime, though the statute of limitations has to be long gone by now
...but as I recall, one might perhaps dissuade a neighbor with an offending nearby outdoor yard light by killing it several times over the course of a few weeks from spending the $ to replace it yet again. If you go this route...a tip. Sidle around to at least 90 degrees from your own place; 180 is even better. Even dumb bunnies can figure out line of sight forensics
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And here is the grown-up Burnham part of the story, from a different place and time. We lived on a different property in the former story.
Here on our place, maybe 25 years ago, a new owner to the next door property put up a giant halide security light in front of their barn. The damn thing was at least a 1000 feet from our house, but it lit up our bedroom like a Hollywood film set. I just visited with them, explained the issue, and asked if they maybe could put the light on an as needed basis rather than "dark comes, light is on until dark goes".
They were more than accommodating...even dropped by to tell us they had stopped on their drive nearest to our house on their way in the next time they were out after dark, and were stunned at the lightshed from that security light. They moved the light within a couple of days to the opposite side of their barn, discovered it lit their bedroom much brighter than it had ours, and not much later in a driveway visit, reported that they quickly decided to shut the light off unless they needed to be out at the barn.
So maybe, John...might you be able to find accommodation with a face to face talk?