The main debate on the Second Amendment has always been whether they meant it for everyone or just state militias. Everyone always forgets the first line of the Amendment in their arguments for everyone gets a gun.
Amendment II
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
Its always been interpreted by the Supreme court to mean everyone, but it could be interpreted has just those who are part of a state militia have the right to keep and bear arms...
Oh and arms isn't firearms, that's a misnomer. Sword and Axes and other melee weapons were still more common in that time period.