So as I’ve said before, I’m not anti-gun, but I am strongly anti-irresponsible gun owner, which I say just so I don’t sound like I’m playing devil’s advocate, because I’m genuinely interested in the opposing viewpoint here.
wouldn’t reducing the number of guns in people‘s possession / inflicting stronger penalties on improper storage or use also lower the chances of them also winding up on the black market?
If you make it harder to buy and ‘disappear’ them, it’s harder for them to get to the kind of criminals and people who shouldn’t have them.
What would happen if we reduced the number of guns in people's possession to zero? There'd be no gun crime. But criminals who are stronger than their preferred victims--almost always young men, full of testosterone and low on IQ points, sometimes in groups--would be free to engage in violence on smaller, weaker individuals with no fear of deterrence. We'd see an increase in muggings, home invasions, rapes, etc. Probably a lot more strong arm robberies in the inner city, forcing the remaining small businesses to leave. So "reducing the number of guns in people's possession" is not a worthwhile goal, or an acceptable means to whatever goal you're trying to reach.
Making it harder to buy guns--and it's already a fairly involved process in most cases--just makes it harder for people who need a gun in a hurry to get one. If you have a stalker, or a death threat, or your car was stolen and you have to walk through the hood to get to your job, you don't have time to deal with waiting periods, NICS outages, ATF forms, CLEO signatures, etc. Every one of those steps is a delay of days (or months) and another chance for something to go wrong, inadvertently or intentionally.
Storage requirements are just a means of excluding the poor from owning guns. An RSC or a safe is a big investment. And depending on the construction of your home, or the restrictions placed on it by your landlord, you might not be able to get a big, heavy RSC to hold your long gun and a few pistols. And as soon as the first RSC is broken into, the government will tell everyone RSCs are crap, you need a TL-15 now. That will price almost every gun owner out of the storage market. We don't tell people how to store their prescription drugs, or their cash, or their sports cars, or their knives or baseball bats; why tell them how to store their guns?