US gang and gun culture, I guess? Not sure what you're getting at. Having strict gun laws in IL for example, didn't stop the south side from continuing to be the wild west. Maybe the stats show violence down, I don't know, but it seems by and large the gun-loving gangsters still got the tools of their trade just fine. No reason the same wouldn't be the case in LA.
To be clear, I agree with tighter regulation in general, but I'm also mindful of the fact that 'hardcore' regulation is unlikely at a federal level anytime soon, and for the most part...criminals will still want, and get, guns one way or the other.