Actually trained soldiers like those in the British military could shoot 3 times a minute, elite units could shoot 4 times. And that was the musket. Fully automatic weaponry did exist when the constitution was written, and more to the point, the purpose of the constitution was to ensure the people would always have access to the same weaponry the government does.
Acting like guns are the problem, is the problem.
Countries with gun control or strait up bans often have mush higher murder rates, but nobody cares about murder, unless several are committed at one time.
Also, "bump stocks" do not turn semi-automatic weapons into automatic ones, they simulate a higher firing rate yes, but with an even further reduction in accuracy over truly automatic weaponry.
As anyone with proper training knows, automatic weaponry is only effective for cover fire. As targeted firing requires accuracy and even military grade automatic weaponry with bi/tripods trade accuracy for the ability to lay down effective suppressive fire.