Continuous and unqualified violence is an essential concept in seeing how the Tommy Gun changed, and even more so why it did at all, especially regarding how it changed hands. We can best understand this change when we think about the relationship between a Tommy Gun and the person wielding it—more specifically, how the person's usage changes due to two factors: the Tommy Gun's unlimited violence and the context he finds himself in with the gun.
Let's start by considering the direction, or flow, of violence when using a Tommy Gun. The direction of violence that Thompson intended is fairly obvious and simple: he imagined a gun that would simply be used by a soldier against an enemy. This is apparent by how he tried to sell the gun directly to the military, but also by his design for the gun--you don't develop a gun capable of continuous and unqualified violence if you want the gun to be more precise than "Soldier killing Enemy."
Think of it this way: On a battlefield where a soldier's only goal is to kill the enemy, there are under most circumstances no other considerations to take into account. The goal is simple, and similarly the soldier just shoots the gun and, because the gun is continuously violent, just keeps shooting until the goal is accomplished or until there's no more reason to shoot. The weapon makes perfect sense in this context, then: it's extremely powerful and can get the job done quickly and without most other considerations that go into firing a gun. The spray of bullets is wide and thus discredits the need for accuracy, and the gun shoots continuously so finding cover to reload is not as much of a priority. Moreover the submachine gun is as powerful as a machine gun and portable, so strategic placement is not as much of an issue, either, since the infantry unit can easily move, gun in hand and likely still firing.
What changes everything, however, and what the creators of the gun didn't realize until much later, was that when there are other considerations the Tommy Gun becomes much less appealing because of its capacity for continuous violence. For instance, one issue that the military brought up was the economy: the gun is extremely powerful, sure, but also shoots so many bullets, many of which may miss or be unnecessary shots that would result in wasted ammo. Take into account that a soldier might find little need to stop shooting in the middle of battle when he is trying to hit an enemy and you have many bullets wasted, and as a result many dollars as well.
Even more noteworthy is the consideration of regard for other human life besides the enemy. This may seem too obvious or even a common issue with the use of any guns at all, but for the Tommy Gun the effects of such a consideration are damning given the right context. In the earlier "soldier versus enemy" example the situation is simple, but what about during a time of peace? Policemen would surely have a use for this continuous violence against gangsters in the 1920's, right? After all, the gangsters themselves used it to great success, so why not make the playing field equal?
The problem is that the playing field is unequal by necessity, simply because of the nature of the Tommy Gun. Especially in cities where Tommy-Gun-toting gangsters were found in the 1920's, where there were criminals there were innocent crowds as well. Auto-Ordnance touted the ability of a Tommy Gun to easily take down a gangster's getaway car in a chase; but what of the citizens walking down the sidewalks? Even in close and private quarters the gun's capacity for violence was too unwieldly--there were many reports of policemen letting loose inside buildings, thinking they found hidden criminals but really gunning down innocents (Ellis 1986). The Tommy Gun was too easy to fire, too easy to hit with.
So who, then, would make the best customer and find the best use out of the gun outside of conventional warfare? Those who didn’t care about these problems—gangster and criminals. This comparison illuminates exactly why the gangsters of the twenties were so quick to jump on the Tommy Gun: they merely saw it as a thing capable of continuous and unqualified violence. They weren't worried about killing innocents in the process. The comparison boils down to a simple matter of means and ends. Because the Tommy Gun got rid of most of the limiting factors of a gun (maneuverability, reloading, the need to aim precisely), it really became a thing that was only as powerful as the shooter's belief in their desired end, subtracted by their considerations of the means. To finally tie it in with the gun-human relationship itself, a gun capable of this continuous violence can only completely fulfill its role as a violent thing when the human and ethical side of the relationship has a diminished impact.
This claim seems fairly convoluted but is actually quite simple: the less regulation the human gives the Tommy Gun, the more powerful the Tommy Gun becomes. By extension, the Tommy Gun produces the most violence in situations where the human in the relationship doesn't care about anything besides killing the enemy. From here we can devise a sort of weighted scale that shows how the Tommy Gun changes from one time or place to another time or place: in the hand of a soldier or a gangster it is lethally efficient, while in the hand of a policeman or in a military strategy meeting it is too dangerous or too costly. The thing-person relationship is an abstraction of this balance, and directly affects how the Tommy Gun is used. Changing its use changes the gun itself simply because of its nature as a tool. The conclusion we can derive from this is fearful—not only is the gun horrifically violent, it becomes more capable of violence almost solely as a matter of the shooter’s ethics. It was the perfect weapon for a heartless killer. (Could Thompson really overlook this capacity?)
This relationship makes even more sense when we return to the gun's limitless violence. What has been said thus far really makes the case more distinct: the gun's violence is unqualified only in terms of the gun itself. With the physical and engineering limits of the gun's ability to produce violence gone, the only limitations left are those of the shooter--in other words, the other half of the human-thing relationship. This is why the Tommy Gun's evolution is different than that of previous guns: with physical and engineering limitations gone, gun violence was no longer a skill that relied on aim or maneuverability, it was merely a switch for violence, to be turned on and off. Either the gun shot and likely killed, or it did not. Aside from mishaps or serious incompetence there were no extraneous considerations of skill, only of who to shoot at and when to pull the trigger.
Thus we can finally see one facet of how and why the Tommy Gun changed, and how it was a shift from previous developments of violence in weaponry—what was more important was the limitations of the shooter changing, rather than those of the gun. The Tommy Gun's use, and thus the gun itself, changed as these limitations changed, from police reluctantly taking down a gangster in a crowd to a soldier gunning down an enemy German. With this we can also finally realize why the Tommy Gun was so commercially unsuccessful in America until World War II—from 1920 to 1944, the only people in America who could benefit from a thing capable of continuous violence were gangsters, who wouldn't be counted as a legitimate sale anyway. (This claim is made fairly clear when we consider that a Tommy Gun on the black market went for four to eight times the legal selling price of about 200$ (Helmer 1969).)
From here you can go to:
Social Acceptability: How Does Society React To Unqualified Violence?
Or, if you've finished all three:
