A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.

Does that sound like what we do today? Nope.

Why does the government infringe on my ability to own a machine gun or even a molotov cocktail?

It seems like the gun debate isn't over. We've constantly reinterpreted the 2nd Amendment over and over, and it will be reinterpreted further in the future.

Today, we heavily regulate machine guns but not rifles. Tomorrow, maybe we can choose to heavily regulate hand guns but not knives.