My personal belief is that the average gangster, who for example recently bought a gun, doesnt have any shooting skills. Obviously from a very close range almost anyone can complete the job and in time, the more he's involved in the shooting job, the more he gets skilled. Also a lot of criminals carry guns just because they want to act tough but dont have the balls to pull the triger or maybe they are afraid because they could miss.As for the professional hit men, at the beginning they obviously train on some private shooting range and learn about weapons. They also train on how to shoot from a moving car or motorcycle. There are some reports which show that during the late 1920s one young and disorganized group in Chicago taught their newest members on how to use the getaway cars during robberies so i can only imagine on what is going on these days for example in the Mexican underworld and their kind of trainers. You obviously need trained skills so you can fire an ak47 while your buddy is driving the motorcycle on high speed. Thats why in the old days the hit squads used to be something like seperate factions within some of the syndicates.I believe that it mostly depends on whos the mentor or what kind of individual is he, meaning is he a business type or the murderous type