If you want to cherry pick certain parts of the second amendment - I can do that too: "the right of the people to keep and bear arms shall not be infringed".
Law evolves along with technical progress and 2nd amendment is not exception.
Also there were repeating rifles, cartridge based rifles, and citizens owned artillery pieces and war ships in the era in which the Constitution was written.
You should read Heller - Justice Scalia wrote a great deal about your argument and why it is absurd.
[1] https://www.brennancenter.org/blog/constant-evolution-first-...
But not to the point of banning speech.
https://mtsu.edu/first-amendment/article/1044/communications...
"The 1934 act designated broadcasters as speakers — thus granting them First Amendment rights — but the broadcast media were also treated as possessing a somewhat lesser claim to First Amendment protections than the print media. The Supreme Court’s decision in Red Lion Broadcasting Co. v. Federal Communications Commission (1969) upheld the principle that the scarcity of frequencies put broadcasters under public obligations to present multiple viewpoints, which therefore served as limits on their First Amendment rights."
A machine gun is nothing compared to a strategic asset. If we want to go back to that model, which is what you argue for, I'm getting a Davy Crockett for my front yard, an Iowa class BB for my dock, and a squadron of F22s and F35s.
Who cares about an M16 at that point.
You're arguing something that simply isn't so.
Benjamin Franklin was an inventor - if you think when they wrote the second amendment they didn't think "gee, maybe guns will shoot faster someday" then I don't know what to tell you.