Clever, but liberals just say the weapons are coming from the suburbs around Chicago where guns aren’t controlled/banned enough.
The reality is though that the idea that gun bans work is an article of faith for liberals. There is no evidence you can provide that will change the way they think about this. The only thing that might is if said liberal gets mugged or otherwise injured by a criminal themselves.
Liberalism is like a religion. For a lot of progressives, their politics have in fact replaced religion. Just like any religious belief, it is extremely hard to change peoples minds about these thing no matter how much evidence is presented.
At the risk of being cliche... see my tagline: