It's common for me to hear gunshots at all hours of the day where Catonsville meets west Baltimore. You can tell they're gunshots because the sound of the bolt changes the pitch of the bang, unlike fireworks.
We also get the police helicopters buzzing around with the spotlight on.
I live in Brooklyn about 250 yards from the Balt. City/Anne Arundel Co. line - I can see the line from my front porch (the streetlights are different). Gunshots are not at all uncommon, and we call the police helicopter "The official bird of Baltimore City". You also get punks on motorbikes zipping down my one-way street the wrong way. (I once called the city police on 311 to complain about motor bikes. When I didn't see an officer in 30 minutes, I called again and informed them the next time someone calls from my street, it's going to be a 911 call after I shot the b@st@rd. The cops were there in less than three minutes!)
Once the weather gets nice, the knuckleheads starting coming out in droves. In all honesty, it's relatively safe - notwithstanding the A.A. county cop who was shot 100 yards from my home last year. However, there are parts of Baltimore that look like third-world countries - you just have to avoid them.