Who said anything about guns? Knives or pipes are plenty common, and in some cities its simple overwhelming numerical superiority. One friend told me of being mugged by ten or so adolescents who were not fully grown or armed. But apparently quantity has a quality all its own. Another friend was in Madrid when pickpocketed, and ran down the thief and used force to retrieve it. He was later told by locals that if he had been seen by law enforcement his penalty would have been much more severe than the thief's. That is all amecdata, but something cultural or something in policy seems a more likely culprit. Some south american cities have pretty tight gun laws too don't they?

That is assuming murders get caught, convicted and sentenced.

"Among the nation's largest cities, Chicago stands out for both its high murder rate and for the number of its murders that go unsolved. In recent years the police have been solving about 4 of every 10 murders in the city, but police data show the rate is even worse when the victim is African American."

See https://www.npr.org/local/309/2019/10/09/768552458/chicago-s...