While there are no numerical limits on the quantity of ammunition one may buy today, Carnac the Magnificent might easily predict that in the not-to-distant future, this will be deemed a “loophole” that the State will endeavor to close. "
... The right to bear arms for a legal purpose is an inherent right even pre-dating and transcending the Second Amendment. "The right there specified is that of 'bearing arms for a lawful purpose.' This is not a right granted by the Constitution. Neither is it in any manner dependent upon that instrument for its existence." United States v. Cruikshank, 92 U.S. 542, 553 (1875),
He got this part right about Miller...
The Supreme Court also recognizes that the Second Amendment guarantee includes firearms that have "some reasonable relationship to the preservation or efficiency of a well-regulated militia." United States v. Miller, 307 U.S. 174, 178 47 (1939). Miller implies that possession by a law-abiding citizen of a weapon and ammunition commonly owned, that could be part of the ordinary military equipment for a militia member and would contribute to the common defense, is also protected by the Second Amendment.
However, I noticed that once again, the author misunderstood another part of Miller. Note the disconnect between the bolded bit above, and the parenthetical bolded bit below. The above bit is correct, but the below bit is not, and in fact, contradict each other.
...One, the Second Amendment extends to common modern firearms useful for self-defense in the home. Two, common firearms beyond just 48 those weapons useful in warfare are protected. See Caetano, 136 S. Ct. 1027, 1028 (2016) (per curiam) (quoting Heller, 554 U.S. at 582, 624-25); contra Kolbe v. Hogan, 849 F.3d 114, 131 (4th Cir. 2017) (weapons useful in warfare are not protected by the Second Amendment).
The parenthetical bit I bolded mistakes Miller badly. Here's a bit of relevant text from Miller:
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 two bolded bits from Miller above say something completely different. What it means is that the Supreme Court had not been briefed that sawed-off shotguns were useful in warfare (as was the case of trench-guns in WWI (which was the "Great War" at the time, since WWII hadn't yet come up). Had the court been informed that sawed-off shotguns were military weapons, the above indicates they would have made a much different decision in this case. It also means that automatic weapons are definitely Second Amendment weapons, and the laws regulating them, which were also not briefed in the case, even though they were a part of the law in question (922o).
U.S. v Miller is one of the most lied about decisions the Supreme Court has ever made.