But in a nut shell if your neighbor can hear the gun fire even if the law is on your side it will not be long before they will have the law changed.
I speak from experience
I was shooting .22s with the land owner on a very large piece of property. The nearest neighbor was a good 1/2 mile away. He called the police on us. After the police told this neighbor that we where well with in our right to shoot, this just pissed off the neighbor to the point that he called the Chief of police. After a formal police investigation that found we not only where well within our rights, we even went out of our way to make a very safe shooting area. Once again this just pissed off this neighbor so he contacted the politicians that represented that area and they changed the law to make target shooting illegal in that area.
I still hunted on that property for a few years after this and every morning during gun season I always shoot deer with the biggest gun I had all within 15 minutes of sunrise.
Check the Howard County Zoning Reg's. Do you know what Zone you're in? The County's certainly tight on us. I know there's a 500' minimum for some shooting, but I've never checked it since I live in Carroll County... and live on such a small lot that I couldn't shoot a pop gun without violating some law. I'd be happy to look into it for/with you. I own/operate a land development firm in Ellicott City and deal with zoning all the time.