Getting legal access to high-performance rifles similar to military weapons is pretty trivial. Easily concealable weapons like pistols usually are more difficult to get a hold of legally.
The legal environment doesn't always translate into reality. I live in a small upstate NY city where we unfortunately have lots of shootings, mostly between poor high school kids. The local drug gangs make "community guns" available in public places like parks.
I would never want to own one, but for someone like me to own a handgun for target practice, there's an onerous process. I'd be required to get training, get background checked and go through a permit application process. After that's done, it's up to a county court judge's discretion, and in this county, the answer is usually "No."