A trivia bit from Prohibition-era Chicago was that, other than pistols, the urban weapon of choice was the Thompson submachine gun. It worked well in an urban setting (.45 ACP with high rate of fire, and easily disassembled to take up a smaller area for concealment.)
However, when the city gangsters tried to move downstate into the rural crime territories, they soon learned that the submachine gun was far less effective than were shotguns.
But, into modern times, cities in urban decay, adding accurate high velocity rifles to the mix makes a great deal of sense. That is, a group can use a sniper both as security when both they and their enemies just carry pistols, and to attack their enemies at a considerable distance.
As a tactic, it is far superior to drive by shootings.
—and in any case, the damage to “civilians” was minimal but the scurrilous media of the day (like now) headlined it into something and an unprincipled malAdministration passed the National Firearms Act-—