It's one of my favourite movies. I watched a walking tour on YouTube of the filming locations in Hope BC a few years back, it was pretty interesting with lots of fun facts. Nighthawks (1981) is also pretty gritty and has Rutger Hauer. A lot more recent good gritty Stallone movie is Cop Land (1997) from James Mangold, saw it for the first time a few months ago and really enjoyed it.
Can you tell I like Stallone? Went and watched a whole bunch of his movies in a row not too long ago and they're really hit or miss.