There are many associations, congregations and clubs (incl. perhaps labor unions) that can fairly be described as a group of people, but corporations are not among them. Most of the owners of corporations are not even human themselves. If we’re going to call a corporation a group of humans, we may as well call a dog a group of fleas, or the White House a group of termites.
In earlier days, the higher-paid employees of a corporation were often expected to make political contributions suggested by their bosses; they knew that future salary hikes depended on compliance. Was it complaints about this practice that eventually led Scalia and the Wingnuts to make their dehumanizing rulings?
The individual right to keep and bear arms won’t survive the first challenge to make it that high. Also every conceivable restriction will slide through like greased lightning.
So many associations (AARP, NRA), Congregations (churches, mosques, temples), clubs (boy scouts, Boys & Girls Clubs of America) and even labor unions (AFL-CIO, AFSCME) *are *corporations and/or have affiliated corporations.
The AARP and NRA have clout on Capitol Hill precisely because they are groups of people expressing a unified voice. The AFL-CIO has bargaining power because it substantial membership of people uniting to negotiate for better working conditions and better pay.
Society could make a decision to provide an alternate means of organization for other than profit making business, but as it stands even very philanthropic organizations of people use the corporate form as a means of organization.
Technically, you could simply say that the framers of the constitution had specific black powder weapons in mind when they wrote that clause. As a side note, apparently even convicted felons are allowed to posses those types of firearms. You are also allowed to have a black powder cannon, apparently.
Anything more modern can be restricted. That may sound harsh, but almost everyone agrees that nuclear weapons and long range missiles shouldn’t be purchasable by individuals, so there is some restriction on the ability to bear arms granted by the 2nd amendment.
A ban on every weapon not available during the lifetimes of the framers would be de facto the same as the heavy restrictions in England or Australia. It could work - if getting caught with a banned weapon is a felony with a mandatory minimum, eventually even criminals would mostly stop carrying them.
A sort of science-fictiony way to find all these weapons would be nanoscale sniffers that look for nitrocellulose. In principle, a house by house search of all of America, where the authorities have some kind of sniffer, could find most of them.
Evidence says total homicides would drop, but some of the people killed by homicide would have been able to protect themselves in a world where they could legally buy guns.