Quite true. You never explicitly said a word about flintlocks. And now, for the benefit of the class, I'm going to do a little exercise. We call it logical reasoning.
Your position is that "to infringe", relative to the fundamental right to keep and bear arms, means only to completely destroy the right.
So how does one destroy the right to keep and bear arms? By completely preventing its exercise. As you have said before, if a person possesses a firearm, then they can be said to be enjoying their right to do so. Therefore, the possession of a firearm, any firearm at all, is evidence that the right to keep and bear arms has not been destroyed.
Therefore, (and watch carefully, because what we're doing here is what grown-ups call "logical reasoning"), if all guns are banned except black powder, muzzle loading flintlocks, then people are still legally able to possess such firearms. A person in possession of such a firearm can be said to be enjoying his right to keep and bear arms. If a person is enjoying a right, that right has not been destroyed. Therefore, per your definition of infringe, a complete ban on all firearms except black powder, muzzle loading flintlocks is completely compatible with your demented interpretation of the 2nd amendment.
Now, if you are not happy with the outcome of this logical, please feel to explain why your initial premises cannot lead to the conclusion we reached.