Gun scare people. Scared people with guns fire more bullets. More gunfire scares more people, causing them to buy guns for protection. Now those additional scared people with guns use them, bringing that same fear they feel to more of their neighbours, who respond by buying guns to protect themselves...
If you really want an armed populace just make it mandatory for all citizens to complete 1 year of military service, with the people retaining their service arms at home. This way everyone is trained the same way and follows the same standards with their weapons. This takes the 'cool' factor out of owning guns, takes the identity politics out of it, and the criminals will now know that they likely cannot gain the advantage in fire power just by getting a high capacity magazine.
It would also calm the cops down, because the year of manditory service will weed out all the crazies that cant handle the responsibility of gun ownership, and since everyone went to the same program you have an automatic national database of who isnt fit for ownership. Give mental health proffessionals the ability to flag on the database when an idividual is having issues so their weapons can be TEMPORARILY removed untill their mental health is restored.
The 2a guys will also lose their main talking point: government is the one giving them the gun now, they would look stupid REEEing about 'gubberment wants muh guns!!'
It seems like the USA will never say no to guns, so why not go full ham instead of just letting every state make up its own rules as it goes along? The current system has some very obvious flaws. Freedom should not be free, it should require responsibiliy, the proof is in the never ending american gun tragedy.
Edit: accidentally tripple posted, still learning the UI... deleted the two duplicates, and fixed some bad grammar