“Possessing a live grenade is illegal.” https://www.criminaldefenselawyer.com/resources/criminal-def...

Obviously there’s a bunch of exceptions, including as you point out the federal option of going through a background check and paying 200$/grenade. But that’s only at the federal level it doesn’t necessarily meet state requirements.

The rules on those background checks are as capricious as banning people who were dishonorably discharged from the military.

Actually things that are new after the constitution was written is regularly brought up before the court it’s a very common argument. The thing was written a long time ago, everyone involved in the process acknowledges that fact. The degree to which papers applies to electronic data should be familiar to you.

Supreme court rulings are arbitrary as they regularly reverse or update standards, sometimes multiple times.