Common sense regulations?
The use of machine guns in crimes were never an issue. Most of the Thompsons and BARs that made "the '20s roar" were stolen from police departments and National Guard armories.
FDR had to do something to keep the Revenue Men employed after Prohibition was repealed. The NFA wasn't about crime at all.
NRA Life Member
"Had King Kong showed up in Texas, Frank Hamer would have taken him down with his Model 8 in .35 Remington...well, he was kind of big, so maybe his BAR"