Remember originaly handguns were going to be NFA weapons as well and were only dropped from the NFA list at the last minute.
Exactly. The NFA intended to ban handguns.
Handguns then, just as now were the most widely used arm against other humans, in both crime and self defense. So they were a larger concern than the machineguns and other objects in the NFA. Arguably handguns were the primary thing the NFA was designed to ban, the other objects were just extras.
For the same reason they also had the most opposition to being banned, as far more Americans owned handguns than submachineguns etc So the NFA might not have passed if it kept the handgun ban. The antis ever mindful to ban what they can, essentialy crossed out the handgun portion (figuratively) and passed the rest of the legislation.
Handguns being illegal means very little if someone can just cut down a rifle or shotgun to similar dimensions.
So limits on long arms were placed with the intent of keeping them from replacing the outlawed handguns.
When handguns were removed from the NFA restrictions at the last minute, the portions of the legislation that were designed to compliment the handgun ban, remained.
So limits on the length of rifles and shotguns became law, even though the intended purpose of that restriction no longer existed.
So what resulted was not intended. The logic that existed at the time behind the size limitations no longer existed.
Since then people have created new logic in an attempt to explain or justify the restrictions.
I would venture to guess someone had a cow over a sawed off and someone else thought.. hmm yea thats bad, unless you send us $200 THEN its okay..
Remember at the time the Congress (and the American people) did not believe they had police powers. They felt they had no authority to ban what they wanted. (That would later change in a future court interpretation on what was allowed under the interstate commerce clause.)
They did however believe they had the power to tax anything they wanted. So they imposed harsh taxes to ban things. They did that with the NFA as well as other things they wanted banned. Take the Marihuana Tax stamp as another example in the 1930s.
They put tax payment methods in place that most citizens would be unaware of. Violation of those taxes then allowed federal punishment.
This was before the internet, and also in a time when things like registration were viewed as extremely unconstiutional by most.
So a requirement to sign up to both pay what amounted to thousands of dollars today (in the middle of the depression), and be unconstitutionaly registered, with a process most did not know about was for all intents and purposes a ban.
So it never was to collect $200, it was to ban possession by average citizens.
That was just the only pretense they felt they had at the time.
They could punish people severely for violation of a tax law, but they could not officialy ban things they wanted to ban. Remember even prohibition was done with a Constiutional Amendment, not simply passage of a law (like things are banned today.)