Heller I believe also used this phrase or a similar one, and I have a problem with that. The AR pattern modern sporting rifle is in common use today, but there was a time when it was innovative and not in common use.
If you make exceptions for innovative weapons, you are in essence "freezing" the list of "approved" weapons.
The “common use” is a minor problem, compared to “the legislature has the power to regulate.”
This amendment would be a large positive step.
Confirm that people have a right to arms; there is a much better chance that they will insist on a right to the latest arms, as they are invented/created.