UPDATE
First, to answer some questions and criticisms...
Why didn't I do something simpler and cheaper, like snip the camera cables? Well, the short answer is TRESSPASSING. Jumping the fence to get into his yard just seemed like a very big line I didn't want to cross. Although he did it quite a few times. Still, being caught doing that would have been bad. Very bad.
As far as less invasive ways to cause damage other than the air rifle... I did try salt water, sugar water and high power lasers. Ultimately these and other more "creative" methods, while fun to write about, are hard to verify. There's just no way to know if any of these would have done the trick. On the other hand, shooting out a lens may be barbaric and old fashioned, but at least it's easy to see when you've achieved your goal. And it's a pretty good bet that a camera with no lens isn't going to be recording anything!
Another reason I decided to just screw it and go redneck is when I found out my downstairs neighbor (who's balcony also faces his yard) was very upset that it looked like one of the cameras was recording HER home. And upon closer inspection, I think she was right - it did look like one of the cameras was aimed a bit lower, and it also makes sense - he wasn't 100% sure I was the culprit, and in practice there is no reason he needed two cameras recording exactly the same thing aimed at my place.
She even went to the police about it but they told her too bad, there was nothing they could do. If she didn't like her apartment being secretly filmed, "move" was their advice.
Well that really pissed me off, and now there was a damsel in distress! She was forced to hang new curtains and stopped going on her balcony.
This would not do.
So, I got the rifle. And keep in mind, when I went to the sporting goods store my intent was to buy a high power WATER gun. I hadn't even considered a "real" gun. But when I got to the top of the escalator, staring me right in the face was a table full of BB and pellet guns on clearance sale. And right on top was a really bad-ass looking 1200 feet-per-second rifle. It was almost like it was meant to be. And the normally priced $160 item was only $99.
And to further make the case for fate, it turned out that the $99 tag was a mistake, and it should have been $129. But since I had picked up a box that had the $99 tag on it, even though it was a mistake, they would honor it.
So I whipped out my smart phone and looked up reviews. They were very good and basically said the rifle in question was really top-notch. So, realizing that this would be the only way to insure success, I went for it.
As documented in this thread, I only took shots while I had a bright light flaring out the lenses, so there was zero chance of me being recorded doing it. And yes, the rifle was pretty loud, so I would take a single shot and then scoot back inside before anyone would have a chance to look around and see where the noise came from (but, to be honest, in a fairly urban area, no one really pays attention to things like that. It sounded like a small firecracker).
Luckily, the scope on the rifle was excellent and it turns out I'm not a bad shot, so I hit the target about 80% of the time. So after about a week and a dozen shots, those lenses were toast!
When douche-face got back from vacation, he called my landlord and complained. The landlord called me and asked if I knew anything about his cameras being destroyed (interesting to note is that the guy wasn't specifying they were shot out - I don't think he knew how it was done. In fact I think he assumed someone jumped the fence and did it by hand).
I sort of evaded the question and told the landlord that the guy is a kook who wanted to blame me for everything just because I had previously complained about his barking dogs. I also pointed out that I wasn't the only one upset about the cameras and our entire building was up in arms about them. The landlord's main concern was the situation would spiral out of control, but I reassured him that since the dogs hadn't been barking lately, as far as I was concerned it was a non-issue that was already over with.
And I reminded him that the guy was nuts anyway, since the whole situation was his fault in the first place - he was ignoring the complaints of his neighbors while obviously being aware that his dogs had been creating a giant nuisance that he refused to do anything about. So he didn't really have much of a right to be mad about people wanting to do something about it themselves.
The only thing the guy did to try and get even was Tresspass into our property and pull my phone cable out of the mainline phone box in back of the building. I was thinking about letting him know that what he did was a federal felony and we had him on tape doing it since there were security cameras all over our building and he was a pretty big idiot for not noticing that (kind of ironic, huh?)
We didn't really have him on tape, but I think he would have believed it because we DO have cameras everywhere - just not back there. But I decided to let it go and not push the situation any further.
And so that's the end! Nothing had happened since then and the dogs have been quiet.
As for the rifle... It sits under my bed, just in case