Solving gun violence in the US in today's insane political climate requires a solution that makes it painless for everyone.
First that this idea even needs to be broached in the first place is ridiculous especially given the lack of clarity in the second amendment (eg it does not specify types of arms so that should be handled by laws not as a "do what you will free for all").
That said it seems there are some major elements that would be necessary to reduce gun deaths in the US and there are some obfuscating interests embodied in the NRA that must be sidestepped or accommodated in the solution.
Four main areas of focus jump out to reduce gun deaths:
1) "mass killings" (included in this would be the 2 or 3 person shootings as well as as Newtown or Aurora types)
2) Accidental shootings
3) Non-owner shootings (eg the shooter is not the owner of the gun)
4) "black market" trading
Added to these I would say the parameter that makes gun control legislation difficult is gun manufacturer revenue stream protection using the second amendment as a shill.
So what are the necessary parameters to make something happen vs. the absurdity of what is going to happen over the next few months in Washington:
1) Figure out a way that shifting policy creates more revenue for gun manufacturers so they get the NRA on board
2) Make sure that guns cannot be used in public places or by someone other than their owner
The Idea - Mandatory gun locks and universal kill switches.
On locks, all responsible gun owners have gun safes. Why not move the lock to the gun's trigger mechanism either with a combination code or biometric locks. That would prevent unauthorized use of the gun by anyone but the owner.
On kill switches, in the same locking mechanism put a chip and actuator that freezes the locking mechanism mentioned above when it receives a certain modulated radio signal.
If mandatory then all existing guns will have to be refitted with the new bolt mechanism creating revenue streams for the gun manufacturers and on all new guns they can charge more creating more revenue.