I work in the criminal justice field, representing many defendants as defense counsel, including organized crime (OC) defendants.
"Gangsters" can mean a lot of different things to different people.
First, you have the punk kids, usually in their teens but sometimes in their middle twenties. These guys may belong to loosely organized gangs, whose principal purpose is street credibility and socialization. Only a limited amount of organized crime is undertaken by the punk kids, usually distribution of pills or pot and occasional very low level burglary. These guys know nothing about guns except what they think they know from movies and video games. Toss a gun into their hand, and they very probably could not clear it, load it, cycle it or fire it. Most of these guys actually carry bb pistols, a completely lunatic thing to do. Some have cheap rifles and shotguns, covered all over with cheap tacticool gear and painted with Testors Gloss Black. Pretty pathetic, all in all.
Second, you have organized criminals. I'm not referring here to syndicate guys, who will be discussed below. Organized criminals may be broken down into actors and associates. Actors are engaged in active criminal conspiracies to make their living; everything from burglary to arson to extortion to theft to drugs, to ... other things. Associates do business with the actors. The associates may enable some of the actors' crimes, but do not typically take active roles in them. Associates typically do not have significant criminal histories, and often occupy positions of respect and trust. Actors typically have been disqualified from firearms ownership at some point in their careers, either as felons, as domestic abusers, or as conditions of bail, probation or parole. Accordingly, they no longer use guns very much, though they may keep a pistol hidden in a wall safe. Associates, on the other hand, not only often own guns, but because of their relatively clean hands, often carry weapons as de facto bodyguards to the actors, in addition to their other duties. Actors tend not to even touch the associates' weapons, for well-grounded fear of legal liability. Full-auto weapons are occasionally held by assocates, and much more rarely by actors; they are never used in actual crimes, as the actors know better and the associates don't want to get involved in wild stuff like that. Much more common are large handguns and small concealable rifles and shotguns.
Finally, there are the syndicate guys, with whom I am least familiar of the three groups. Surprisingly, quite a few of these guys and their associates possess full auto weapons, often legally. It's more a status thing, to show off to their buddies and impress others that their bodyguard detail is heavily armed and capable. Occasionally, syndicate guys actually USE a full auto weapon on the job, but that is rare other than in the case of a desperate wiseguy out of his head and fearing imminent death.
So that's the long way of saying that while there's some truth to the Hollywood myth, the reality of firearms and OC looks nothing like Hollywood makes it out to be.
