I know it's already been stated, so I apologize for beating a dead horse, but I feel it's something that warrants repeating: if you outlaw guns, only outlaws will have guns. Do you really think people who are okay with murdering other people in the first place are going to have a moral problem with illegally owning a weapon?
Now, if I had the option of going back in time to prevent the invention of the gun, I would probably do that. And if there was a way to seize literally every gun on the planet and prevent the production of any new ones, I might support that. But at this point, to fight crime rates by taking guns away from law-abiding citizens (because those are the only people affected by gun control laws - citizens who actually abide by laws), it just seems... pointless at best, counterproductive at worst.