I think guns work well for self defense, but strict regulations are needed given that many people are mentally unstable and can have no control over their violent impulses and special care should be taken in the case of people with psychopathic or manic tendencies, who could end up shooting innocents acting remorselessly and without any considerations, that is, just for sport. Special restrictions should be put on assault rifles and military type weapons, which are rather excessive and, in their free promotion, will lead more to an increase of deaths, criminal and accidental, than real protection whatsoever. That's ideal at least, but there are actors like the weapons industry itself, financing lobbies to protect their interests and maintain high sales, who benefit from no restrictions or background checks, because, the less checks, the more potential gun buyers there will be, and so, millions are poured into lobbies like the NRA and the pockets of mostly conservative politicians.
That said, it doesn't take much thought to figure out how the schemes work when it comes to the weapons industry, but many people feel a sense of entitlement and self-assurance in possessing guns, and a sense of false empowerment in being able to play with them, so they unconditionally support so called gun rights, which only means not restricting guns, a dangerous policy that makes casualties more likely, simply by giving a free pass to potential criminals and manical psychopaths to grab weapons, makes them untrackable, and makes it virtually impossible to establish a tracking system as to who provided it, who bought it, where he got it from, and so on.
No science or anything, just common sense to it, but the problem of violent crime will continue to worsen so long as these variables remain just like this.