Cities like Plano or El Paso have about 2 homicides per 100,000. Gun control cities like Chicago have about 20, and places like Detroit have over 50.
Chicken or egg? Wasn't gun control instituted in those cities at least partly because
there was already a high homicide rate? (Oops, digits
was making the same point at the same time.)
Also, you can't look at a small geographic area, such as a city, in isolation. If it has much stricter gun control than nearby jurisdictions, there are obviously going to be a lot of guns brought in from those jurisdictions.