I mean, personally, my opinion on this issue is pretty much:
Ban legal ownership of guns to anyone convicted of a sex crime, robbery, murder, domestic violence, child abuse, manslaughter, animal cruelty, or any other crime that is considered violent. Anyone with such a prior conviction who gets caught in possession of a gun is given a mandatory life sentence in a prison designed around hard manual labor for inmates.
Stop releasing violent criminals in favor of keeping lesser criminals in jail, that's just idiocy. The only time a criminal convicted of a violent crime should be released is when their entire sentence is up.
A national database of such offenders so they can't cross state lines to get access. Include any convictions that resulted in being found incompetent to stand trial or being declared legally insane.
Have a serial number etched into the gun in an inaccessible location during manufacturing (accessing it after manufacturing should render the gun useless) in order to make guns more easily traceable and less likely to end up on the black market in the future.
If the gun can be traced back to a previous owner/seller guess who gets to join the ex-con in jail for selling to someone not legally allowed to own a gun? (Short of a police report indicating the gun was missing/stolen dated within two days of the gun going missing, "It was stolen" will not be a get out of jail card, if they sold it to someone else, they'd better hope they have a receipt and proof that they checked the buyer out on the national database to cover their ass. your gun, your responsibility to know where it is at all times and who has access to it.)
Initial use and understanding test of firearms that grants class licenses for owning and operating particular firearms on a national basis (like a driver's license for guns with different class access as the gun gets more powerful/deadly without restrictions on how far up the line you can go but is limited only to handheld weaponry, like rifles (including fully automatic even though there's no logical reason to own a fully automatic rifle), shotguns, handguns, etc ) as well as renewing the license every so often to prove continued competence with the firearm under the supervision of a professional trained to catch signs of mental health decline in addition to weapon expertise. Mandatory inspections of your firearms during the renewal process to ensure your weapons are in working order and well cared for.
If your gun is used in a crime and you don't have a paper trail showing it was sold to another person legally, or a police report saying it was stolen, you are on the hook for whatever crime was committed. Again, your gun, your responsibility to know where it is at all times, ignorance is not a defense.
Teachers with classrooms near exits should be armed, tell absolutely no one that this is part of the safety protocol. Yearly training for these teachers to respond to a crisis situation safely and effectively and how to most efficiently take out an active shooter. Training for any willing teachers, up to three per school, in emergency medicine to try to minimize casualties should an event happen.
I may have a bit of a dystopian view of things, but I'm fairly confident legalizing illicit drugs will take care of the majority of these problems within a decade or two.
I'd also like to stop the whole treating criminals humanely thing. It's a waste of resources and removes every incentive to avoid committing crimes. I'm fine with treating non-violent criminals with a certain level of humanity, but they should not have access to better care than the average person, that's ridiculous.
I'm not entirely sure what side of the aisle these views would put me on, but I'm pretty sure most people on both sides would hate them