From Foundation for Economic Freedom:

Gun-control advocates often argue that gun-control laws must be more restrictive than the original meaning of the Second Amendment would allow, because modern firearms are so different from the firearms of the late 18th century. This argument is based on ignorance of the history of firearms. It is true that in 1791 the most common firearms were handguns or long guns that had to be reloaded after every shot. But it is not true that repeating arms, which can fire multiple times without reloading, were unimagined in 1791. To the contrary, repeating arms long predate the 1606 founding of the first English colony in America. As of 1791, repeating arms were available but expensive.