OK, I'll start.......
1st of all - lets start with some definitions and common terms so we can all work from a common language. The 2nd Amendment to the US Constitution is an individual right. The SCOTUS has ruled that it does NOT apply to only militias. Furthermore, the SCOTUS has definitely ruled that a common core purpose aside from defense of the country from external AND internal enemies - is defense of self, of home and of others. You don't have to like it or accept it, but that IS the current law of the land. Don't like it, then change the Connie.
However, the right to keep and bear arms (RKBA) is NOT an absolute right. There can and should be common sense restrictions on gun ownership. For instance, I don't want felons, violent people, mentally unstable people, juvenilles, etc to have access to guns.
Next, I would define "Arms" so we can better categorize them. To me, "Arms" in the context of the 2A are personal firearms that one would reasonably be expected to possess in order to carry out the core purposes of the 2A including SELF-DEFENSE. IMHO, that means "normal and common weapons" up to and including military grade weapons that would commonly be carried by a "person" as an individual arm. I would NOT include in that explosive devices, rockets, artillery, tanks, fighter jets, nukes, MANPADS, etc. Because NONE of those are "carried" as the principle means of a personal weapon. RPGs, grenades, tanks, MANPADs are ALL secondary weapons to the rifle and pistol. The citizen soldier did not keep cannons and naval warships for personal use in 1776. The same will be true as technology progresses...... a phased plasma rifle for the individual will be fine but I would not allow common access to bigger stuff. I don't need RPGs, SAWs, Stingers and Claymores for "self-defense".
Any weapon that meets the "arms" definition is ok. Mag limits, barrel lengths, caliber and such are irrelevant to the discussion of whether it could be used to commit a crime.
The focus should be not on regulating the gun, but on regulating and screening the individual. If you're a convicted felon - no gun. If you're a hard drug user - no gun. If you're violent or mentally unstable - no gun. If you're under 18, you can't buy a gun yourself - and your parents or legal guardian are LEGALLY responsible for you if you misuse a gun as a juvy. That means THEY are fined or go to jail if their kid hurts someone with a gun they own.
I would beef up screening and background checks - to include a database of your criminal history in ALL states. I would mandate BGC for ALL sales including private sales. I would make it possible that instant BGCs could be done over the phone or internet like a dealer can do right now. It puts the onus on the seller to make sure (or at least as best as the system allows) for that gun to not get into the hands of a criminal. If a gun that you own shows up at a crime scene and it wasn't reported stolen and it wasn't transferred properly - YOU are on the hook for the crime. "Loaning" guns to friends and family members could be done as easily as going on line and filling out a quick form stating the name and period of transfer. I would hold each of the transferees to the same instant background check standard as I would someone buying the gun.
The only way to do the above is to have expanded and linked DBs of criminal history updated by the states and feds. (garbage in, garbage out) I would have very strong laws on the books that very clearly describe what the information can and cannot be used for to prevent abuse byt the gov't. We can do it with other databases they keep on us, they can do it for this.
I would significantly increase the penalties on people who illegally possess guns, illegally sell guns and who use guns in a crime. I would make it mandatory in ALL states that guns that are lost or stolen must be reported in a timely manner.
I would make it mandatory that guns are reasonably secured in the home. That does NOT mean that you have to keep it locked up, dissassembled, trigger lock or whatever at ALL times. But if you leave it unsecured and child picks it up and shoots himself or others or if you leave a gun under your bed or in the closet while you're at work and a thief breaks in and steals it - YOU are liable for fines or criminal penalties. A gun safe is not that expensive. If you can't afford a safe or lock, you can't afford (and shouldn't have) a gun. Sorry, gone are the days when you can leave it in a glass gun cabinet at home or in a gun rack in your unlocked truck and think its safe. Yes, I expect my locked house to be safe from burglery, but that's just not reasonable anymore. Being a gun owner comes with a responsibility. Now if someone comes into your house while you're at work and rips the door off the safe or rips the safe off the wall and takes it... that's a different story.
I would strengthen the mental health screening & reporting aspect. This is likely the hardest part to do correctly - but I would make reporting of mentally unstable/violent folks mandatory. I would set up medical health professional boards to conduct screening and in extreme cases have a panel of judges adjudicate the case to see if suspension or revocation of gun ownership is justified. Even if a temp removal is done, that's better than letting a deranged person intent on harm to self or others have a weapon. But along with that has to come a judicial and legal oversight. LEO alone cannot and should not be enough to confiscate weapons or place someone on a "do not buy" list. A single doctor also shouldn't be enough to do this. If someone is enough of a threat - they need to be evaluated by a board docs and then adjudicated by a judge or judges. And there needs to be a speedy process to reverse that and restore rights once the problem has passed.
Finally, there needs to be a concerted effort by gov't and more importantly by society to condemn and shape poor behavior when it comes to misuse of guns. No longer should we accept the "no snitch" attitudes in the ghettos. We shouldn't accept the glorification of poor behavior by hip hoppers who use guns in violent and sexist images. We need to take the MADD approach and treat the behavior rather than the implements.
Thank you for your time and consideration......