CatBus, the Bill of Rights were not a grant of power to the government. In terms of the scope of the right, you quickly run into problems if the federal government imposes all manner of restrictions on individual ownership: it tramples on the state prerogative to have militias. The Amendment pretty clearly protected individual ownership of arms because of the state prerogative. It says so. You’re right that arms are not only guns. For example knives are a kind of arm. The Court held that the scope of the right extends only to weapons that would be normally posessed for use in a militia and excludes dangerous and unusual weapons. That is the originalist holding. The idea that state militias would be compelled to use outdated technology doesn’t make sense. When we consider the free exercise clause we don’t limit it to religions that existed at our founding but that doesn’t make it non-originalist.