If the Rights were limited to the technology of the day, the First Amendment would be limited to newspapers printed on hand operated screw presses. Photography, video, television, radio, would all not be so protected.
With that thought in mind, the Second Amendment was written to preserve the balance of power between the people and their government overwhelmingly in the favor of the people, who would regulate the domestic actions of the Army by the force, if necessary, of their overwhelming numbers and privately held arms. That didn't confine them to pointy sticks and long blades, but instead guaranteed that their right to own state-of-the-art arms as capable as those held by the standing Federal Army would go unmolested.
Otherwise, in the face of overwhelming force, the hopes of being able to preserve the Constitution against tyrannical depredations would be moot. (Not that people haven't thrown rocks in such instances, such as the Pratt Street Riots, but that didn't work very well, either.)
So, the thought remains, that even with the AR-15 and clones or the various look-alike semi-automatic firearms which mimic true military weapons in appearance but do not share their functional capabilities, the citizenry is seriously deprived of the very capability the Founder envisioned, rather than endowed with some undue martial presence as a result of the limited modern technology available to the average Joe, or George, in this case. After all, semi-automatic rifles are well over a century old, as designs go--the first successful ones designed by Ferdinand Ritter von Mannlicher in 1885
(source). We aren't too far ahead, as gun owners, we're a century and a quarter behind.
For there to be parity, George would have had to own an M-4 at the very least, and possibly a more capable weapon (something belt-fed). But at the least he would have a select fire weapon capable of full auto or three round bursts, and not just single shots, fired in sequence by squeezing the trigger for each round sent downrange.