The Second Amendment was approved before revolvers were invented much less bolt action and lever action rifles in the 1800s. The Thompson (Tommy) Sub-machine gun came along in 1918 and in June 1922, Congress passed the Firearms Act prohibiting them. In 1986 the Firearms Owners Protection Act banned automatic weapons with the NRA Support which was before they changed leadership and manufacturers started supporting them financially.
Today an owner of an AR-15 type weapon can quickly and easily be converted to an automatic by an on-line purchase of a couple of parts. The instructions accompanying the parts are so easy Junior High kids could probably do it. Anyone can order the parts.
The NRA and other gun organizations have decided to scare Americans into buying guns manufactured by their supporters. After everyone has semi-automatic pistols and rifles, will they step them up to fancier and more expensive weapons, perhaps a 20 millimeter chain gun as in the movies! Will the next step be to push the most scared of us into highly sophisticated military weapons – perhaps a twenty millimeter chain gun as in the movies? Will Congress fold under pressure from the gun organizations and do nothing? Of course – they want some of that money, too.