It's taught in a Policing 101 class - "Where you find illegal drugs, you find guns."
And the guns you find are not from legal sources. Quite the contrary. They are stolen guns bought on the black market. Or guns from "straw purchasers" who are legal but then sell their legally purchased guns to drug dealers and convicted felons on the street.
And it makes sense from the drug dealer's perspective. He/She is dealing with desperate people who are addicted to drugs. And they are in competition with other drug dealers for supply and clients. If someone tries to "rip them off" they need a means to protect their illegal operation. And that is those illegal guns!
After all, they can't call the police for protection or to report a robbery.
Recently the Federal government has announced that they are going to release thousands of what they call "non-violent" drug offenders from Federal prisons. How naive do you have to be to do that? Where are those generally unskilled, uneducated prisoners going to go? They are going back to their old neighborhoods, to their old cronies who were in the same industry, and go back to their old ways of dealing drugs. Make no mistake, these are not wayward college students who got caught with a joint of marijuana. These are often hardened criminals and gang members who were caught with lots of drugs! And now, from their time in prison, they have made even better "contacts" in the crime world.
And the illegal guns and violence will follow. From my more than 40 years in the law enforcement profession, I can guarantee that most of those "non-violent" drug offenders will be back in the prison system in very short order. For the Federal government to release them back into society today is a huge mistake and will result in serious problems in both our inner cities and our suburbs as they spread their drug culture until they get caught and sentenced once again.