Full autos used in violent acts gained publicity during Capone era when gangsters stole browning b.a.r.s from military armories by at least one gang, Bonnie and Clyde used at least one of their 3, their source was police stations and officers. After the 30s not many references. Though Bonnie and Clyde inspired action in 1934 restrictions that came in place. A hefty tax,fingerprinting and registration.
The N.R.A. only to later regret, went with nodding to 1986 ban as it was near last minute attached to a bill they wanted passed.(but they did know!) Lesson learned,even though few had interest in full autos being owned then, it opened the door to debates over semi autos still going on. While 1934 requirements can be credited with reducing the number of a type of weapon its importance not to be missed is that it caused so few to be in circulation it made 1986 ban "easy". While i can not say what it saved in lives the 34 and 86 rules and regs together may be best successful control example. Like it or not it was effective. Today's semi auto numbers will not tolerate as easy a challenge, more owners and watchdogs involved. So Stocky if nothing else the full auto legislation brought attention to weapons control !