If you can "feel" the bass frequencies of the boom, probably fireworks. If it sounds like more of a loud snap, gunshots. This assumes the shot/blast is fairly far away. That's my best guess.
I used to have a motorcycle that would give a couple of pops out of the exhaust if I closed the throttle too fast. I wonder how many Nextdoor conversations it started?
As someone who lives in country Australia, it's quite common here too. A popular pastime among the young guys out here is to jump into their ute, load up their guns, and go down the highway shooting every street sign they see. I usually hear it every Friday and Saturday night.
I'm British so I'd be pretty sure they were fireworks where I live.
But I'd still be a bit on edge. There's a good chance it's either being set off by a bunch of dumb kids throwing them at each other in the street who'd stab me if I confronted them or by some complete moron who has no idea what they're doing and it could go fucking anywhere.