Is the First Amendment obsolete because they didn't envision the computer, the telephone, TV, or the high speed "assault' printing press?
The flintlock of 1776 was the AR-15 of today. The SCOTUS 1939 Miller decision that is highly touted by liberals, established the MILITIA purpose of weapons supported by the Second Amendment. The sawed off shotgun in the case was not then recognized for it's value in warfare.
We are to have military type arms if we are to withstand the tyranny of an out of control government. That was the purpose of the Amendment (and that of 35 or 40 of the state constitutions) in the Federal Constitution.