What the authors of the 1934 National Firearms Act were really after

Emphasis in places mine:
The most important thing to be noted is that the law was first concerned with the effective registration and regulation of civilian ownership of pistols and revolvers. Machine guns, sawed off shotguns, and gun mufflers/silencers were of relatively less concern, in that order.
So the basic types of firearms the average citizen would have for self-defense were what they really wanted to restrict.
There was near unanimous belief that machine guns could be taxed so as to make them virtually unavailable to the common man.(Chorus of 'The power to tax is the power to destroy') That was already the case because of the price. At the time, the only available sub machine gun was the Thompson. The retail price was $200, and they were not selling strongly. There was only slight mention of other machine guns.

There was somewhat less agreement on sawed off shotguns. Sawed off rifles were added almost as an afterthought.

The hearings never touched on gun mufflers/silencers at all; no reason was given for their regulation. Machine guns were a concern, but they were few in number. The proponents mentioned they were being manufactured illegally by bootleggers.
And the real crux of this:
It is clearly stated in the hearings, that making the law a "tax" was to avoid the potential violation of the Second Amendment. The Second Amendment had not yet been tested in the Supreme Court. The consensus was that States were not restricted by the Second Amendment.
And the Obamacare penalty was made a 'tax' to get around the law.  Etc.

And just like the progzis now, they want that list of people.  For later use.
It was the lobbying of gun owners around the nation, lead by the NRA, that killed the inclusion of pistols and revolvers in the bill. Registration of pistols and revolvers, at no fee, was offered. That option was also killed. The proponents could not give an adequate answer as to why registration was needed.
Three guesses what they didn't want to admit to.

And this will sound familiar:
For example, semi-automatics that could hold 12 or more rounds were initially defined as machine guns. Changing that definition to the current one, where the requirement is that more than one shot results per pull of the trigger, was one of the first NRA successes.

The ignorance of the people proposing the legislation is obvious. It is eerily reminiscent of the ignorance seen in the current debate. Most arguments were based on anecdotal evidence.
Which reminds me of a guy claiming a semi-auto is a machine gun, being called on it, and responding "I don't have to use your NRA-approved definitions!"

The current enemy is the same as the previous; only the names change.