The founding fathers had no vision of the types of weapons the citizenry would have access to in the 21st century to commit mass murders in schools and churches to name just a couple of places.
The founding fathers had no vision of the types of weapons a government could turn against its people. China, Russia, Cambodia, Vietnam, etc. etc. in order to kill millions of their own citizens.
But the founding fathers understood that a government was potentially the greatest threat to the people. Hence the principle that the citizenry would be armed to dissuade the ambitions of the politicians.
BTW-- you do realize that there were repeating weapons with large capacity magazines in the colonial era and that Thomas Jefferson provided one such rifle to Lewis and Clark for their expedition? It was a rifle used by the Austrian Army. (Of course, in the colonial era much of the artillery was civilian owned…)
en.wikipedia.org/wiki/Girandoni_air_rifle
The briefs and rulings in Heller (Parker at the lower courts) and McDonald are fascinating reading on the origin of the Second Amendment, intended to preserve/protect a right the colonists had prior to the new government. The Congress of Racial Equality provided a great Amici brief on the racist history of gun control in the US. Gun control is always about disarming folks to make them more vulnerable.
DC Court of Appeals decision summarizes their decision:
“To summarize, we conclude that the Second Amendment
protects an individual right to keep and bear arms. That right
existed prior to the formation of the new government under the
Constituti¬on and was premised on the private use of arms for
activities such as hunting and self-defen¬se, the latter being
understood as resistance to either private lawlessnes¬s or the
depredatio¬ns of a tyrannical government (or a threat from
abroad). In addition, the right to keep and bear arms had the
important and salutary civic purpose of helping to preserve the
citizen militia. The civic purpose was also a political expedient
for the Federalist¬s in the First Congress as it served, in part, to
placate their Anti-federa¬list opponents. The individual right
facilitate¬d militia service by ensuring that citizens would not be
barred from keeping the arms they would need when called forth
for militia duty. Despite the importance of the Second
Amendment’¬s civic purpose, however, the activities it protects
are not limited to militia service, nor is an individual¬’s
enjoyment of the right contingent upon his or her continued or
intermitte¬nt enrollment in the militia.”
Page 53 of the DC Court of Appeals ruling is pretty interesting commentary on technology not invalidating the principles underlying our rights:
Pg 53
The modern handgun—and for that matter the rifle and
long-barreled shotgun—is undoubtedly quite improved over its
colonial-era predecessor, but it is, after all, a lineal descendant
of that founding-era weapon, and it passes Miller’s standards.
Pistols certainly bear “some reasonable relationship to the
preservation or efficiency of a well regulated militia.” They are
also in “common use” today, and probably far more so than in
1789. Nevertheless, it has been suggested by some that only
colonial-era firearms (e.g., single-shot pistols) are covered by
the Second Amendment. But just as the First Amendment free
speech clause covers modern communication devices unknown
to the founding generation, e.g., radio and television, and the
Fourth Amendment protects telephonic conversation from a
“search,” the Second Amendment protects the possession of the
modern-day equivalents of the colonial pistol. See, e.g., Kyllo
v. United States, 533 U.S. 27, 31-41 (2001) (applying Fourth
Amendment standards to thermal imaging search).
