Gun owners outnumber the US Army 80-1? A bunch of civilians with no military training is going to take out Special Forces units? You ever see a tank up close? I have. No group of civilian “gun owners” is going to have a chance against a tank, let alone a battalion of tanks and artillery.
That’s probably true if the military were focused on a small target.
But what if the federal government tried to use the military to take over the whole country? The military forces would be widely dispersed, and a large percentage of privately owned guns among the population would be a significant deterent.