Who cares?
The Second Amendment protects actual 'weapons of war'; what the heck do you suppose a "well regulated militia" would be armed with?
NFA is the original and blatant violation of the Second Amendment.
The militia mentioned in the 2nd amendment was defined in several rulings by the SCOTUS as a body of citizens organized for military purposes. They then went on to say that when summoned to appear as members of the militia, they were expected to appear with weapons supplied by themselves and of the type in common military use at the time. (Presser vs Illinois, Miller)
Accordingly, the firearms that that citizen militia should have access to should have the most direct military utility of those available. For example, the AR-15 in 5.56 NATO configuration is the closest modern equivalent to the Brown Bess musket. Its ammo is interchangeable with standard military ammunition, almost all of its parts; save those of the fire control group that enable selective fire options, are interchangeable also.
Semi-auto fire from an individual non belt fed shoulder firearm is superior to full auto fire for most tactical situations anyway, save for gaining initial fire superiority, suppressive fire, the final stages of an assault, and when firing along final protective lines in a defensive situation.
We must not be afraid to DEMAND access to military grade firearms, of whatever type, for the individual militia soldier. The 2nd amendment aint about shooting bunny rabbits. It is about protecting the community from internal and external threats, and opposing tyranny. In short necessary to the security of a FREE state.
The Supreme Court agrees with you (and me). From U.S vs Miller (1938)
In the absence of any evidence tending to show that possession or use of a "shotgun having a barrel of less than eighteen inches in length" at this time has some reasonable relationship to the preservation or efficiency of a well regulated militia, we cannot say that the Second Amendment guarantees the right to keep and bear such an instrument. Certainly it is not within judicial notice that this weapon is any part of the ordinary military equipment or that its use could contribute to the common defense. Aymette v. State, 2 Humphreys (Tenn.) 154, 158.
The court was lied to by the government during oral briefs. Sawed off shotguns (the subject of the case) were used in the trench warfare during WWI. The court ruled in favor of the lying U.S. attorneys because they didn't know any better, and the other side was not presented for brief. What the court was saying, was only military weapons were protected by the Second Amendment (which is wrong IMO). The NFA is therefore unconstitutional on its face.