Look how with all of our sophisticated technology, we lost the war in Vietnam (and the surrounding countries we did war crimes in), and we lost the war in Afghanistan. Greater technology doesn't always win, so even the level of arms we can legally obtain could still win a war.

The other thing to consider is that at the time the constitution was written, a single shot musket was not the pinnacle of weapons technology a private citizen could own. You could have a fully armed warship. It's not a good argument to lean on the intention of the founding fathers, because at that time, you could privately own a ship capable of leveling a coastal city. Personally, I think their opinion doesn't matter, anyway, cause they also intended for slavery to exist.