I do not think there is a caveat in the second amendment that says "regulate". Regulate? (As Morty Seinfeld said in the "Low flow shower" episode) "I don't like the sound of that"
It refers to a "well-regulated militia"... which, at the time, mean well-drilled, well-prepared, and well-supplied... and certainly NOT "well-controlled by the government forces that it is supposed to protect us from"!!