In my eyes the most effective means of gun control for the peculiar political situation in the US would be to add fees for their purchase (annually renewing) and to require manufacturers and owners of operable weapons to have a locking mechanism on the trigger with an electronic or physical key. These policies would be helpful by themselves, but more importantly I think they would help in deescalating the conversation and making the issue less politically toxic over time.
The locking mechanisms would help with things like teen suicide and gun theft, but the effects of the increased price of both the mechanisms and the fees would make gun ownership less accessible for people looking to buy and own guns for frivolous reasons. If you had to pay an additional $500-1000 per gun on purchase and like $200-400 yearly each, plus the increased cost the safety regulations add to the market price, more hobbyists, collectors, hunters, the "home invasion" crowd, and others would be priced out and would prefer other hobbies. People who own multiple guns and collectors of many guns would likely prefer to have most of them permanently deactivated or sold rather than pay annual fees on something they don't use, and general rates of ownership and proliferation would drop. And if the industry were maimed in the process, maybe the obviously corrupt influence of money and business interests on the debate would diminish as well.
In many respects, the "responsible gun-owner" group is the greatest obstacle to public policy that makes any sense (despite themselves not having done anything wrong) because their central position in the rhetoric distorts the issues and create a bloc of voters that have a large personal interest in gun legislation only by virtue of it being connected to their hobby. If people bought fewer guns simply because they were more expensive, more people would look at the issue from a disinterested view of public welfare and would be more open to evidence-based policy, rather than considering themselves to be personally under attack and their self-image of responsibility to be personally slighted whenever the possibility of gun control is brought up.
This ^ Is very much a "city dweller" take on the issue.
For city dwellers, who have the benefit of an actively patrolling police force, a municipal animal control department, and a number of other fully leveraged security services available in a short time period in response to a disturbance, the only legitimate reason to own a gun is "hobby", so "taxation to reduce ownership levels" makes perfect sense.
However, I will again point out that huge portions of the USA are not city, and that a good chunk of gun owners are not city dwellers, who own and operate weapons for reasons other than "hobby", directly stemming from the lack of those security resources.
Unless the city dwelling population wants to pony up and be responsible for the marked reduction in security of non-urban populations, by the forced introduction of such measures (Ha!) by providing the same level of security to the impacted populations (HAHAHAH!! as IF!), this is a non-starter to a good portion of the country, who also just so happen to be perfectly legal gun owners.
I am perfectly OK with passing federal level regulations for gun ownership inside cities that might have such trappings. Not so much for them as a blanket "for everyone", since not everyone has equal access to security related services.
I can see reasonable restrictions on the numbers and types of weapons that could be owned, (you dont need an uzi. No. You just dont.) but it is improper to levy such a weapon tax on people who actually need them. It's about as silly as taxing kitchen knives. In fact, kitchen knives make a great analog here: Using a katana in the kitchen and claiming it is essential to carve a turkey is nonsense. However, you DO need a fairly long knife to carve a turkey. If the local government gets a bit paranoid about large knives, you will suddenly find yourself trying to use a short paring knife at thanksgiving. Likewise with animal control out in the county. Sometimes you really do need the extra firepower. (take for instance, against bears.) People who mean well can put you at a great deal of risk, insisting that you dont need more than a 9mm pistol, ever. They simply cannot conceive of how you could possibly need that M1 garand, even when you explain it to them slowly. The concept of "Wild bears + isolated cabin == Need big gun" does not sink in; they insist that is what animal control is for. Even though you live 4 hours away from a major city. They may even suggest "Fish and Game department"--- which is often DAYS to respond.