A large fraction of the harm from firearms comes from their ability to fire rapidly which didn’t exist when the constitution was written. As such it was making a very different balance of risk between the general public and individuals.
Very obviously individuals were expected to be part of the militia, which was the military at the time (c.f. the Militia Acts 2 years after ratification requiring individual gun ownership and very clearly laying out that all able-bodied white male citizens aged 18-45 were part of the militia), but also states could regulate weapons if they wanted.
Not a firearm.
I didn’t say we could ban compressed air powered guns, I specifically said percussion caps. The Girardoni was way less dangerous than a modern handgun.
In the 230 intervening years, we've vastly increased the scope of the federal government and developed a formal military, so one might argue we ought to amend the constitution to change exactly what's allowed under 2A (e.g. it should be straightforward to have a nuclear weapons ban added with unanimous agreement), but as it stands, 2A (+14A) clearly gives individuals the right to own the arms necessary to run a functioning ("well-regulated") militia, which in 2026 means at least semi-automatic firearms.
Thrown stones are a fast firing deadly weapon. They, compressed air guns, and ball musket etc aren’t used by modern military forces in combat because they are less dangerous.
A rule that allows compressed air weapons yet bans percussion caps is quite reasonable and could pass constitutional scrutiny.
Banding heavy machine guns yet another invention after the constitution was written didn’t, so there’s clear present this wouldn’t either.