In that decision Scalia defined enough flexibility in the 2nd to allow it to survive. The same as the first amendment. Rules with too much rigidity quickly become impossible to defend and fall. Positions so rigid as to become unpopular and silly seldom last long in any society. That is what you are up against. Flexibility. In every constitutional amendment has been evident since the beginning. Even the 18th amendment allowed the production and use of alcohol in prescribed ways. If the law becomes so rigid as to loose popularity it will surely be repealed and you will have the risk of loosing it all. Another thing that occurred with the 18th amendment.
But Argo, if we could carry HE grenade launchers, we would never have another bear gun argument.