“There is the Second Amendment.
Unfortunately, it is not being enforced.”
What more would be legal.....?
In a fully enforced Second Amendment, any fee or tax required to be paid to have or carry a firearm would be unconstitutional.
In a fully enforced Second Amendment, having to wait before purchasing a firearm would be an infringement and unconstitutional.
In a fully enforced Second Amendment, any laws against carrying any common weapon in public would be unconstitutional.
In other words, the assumption would be that owning and carrying weapons would be a right, infringed in only very unusual circumstances (such as in prison, or security areas inside military reservations).
That is the way it primarily was before 1900, with some exceptions in the South that came from the federal occupation after the war between the states.