If unlimited firearms was what the founders wanted, I think they would have said so. they didn't
They didn’t want a standing army, hence “the well-regulated militia”. Standing armies were instruments of tyranny in Europe. But they did realize the need to defend against others, especially having just fought a revolution.
And note the correlation of shooter skin colour to health.
What type of guns did they have back then?
The same kinds their rivals had. There were privately owned cannon, and warships.
We don’t limit freedom of the press to 18th century technology either.