End drug prohibition, destroying the drug cartels which fuel gang warfare then Chicago and the rest of the U.S will find the homicide rate likely halved. There is no need to ban guns. That is as effective as banning drugs. Vermont and New Hampshire have the most liberal (as in free) gun laws in the country, but the lowest homicide rates and violent crime overall. I wonder why.
Regulating gun ownership isn't the same as banning guns, and correlation is not the same as causation. I could say "Norway has very strict laws when it comes to owning guns, yet our murder and crime rates are way lower than in the US." and that would in the same way not prove that strict gun laws means less crime.