Not exactly scientific, but there seems to be some things I noticed.
1. If you don't let people have guns or you have strong restrictions on gun ownership, gun crimes do go down. But this presents other problems. The people usually get oppressed by government and usually are a lot more submissive to them. Often you get authoritarian-like governments strong-arming the people because they don't have reason to be afraid of them. The benefit (or detriment, depending on what you want) is more social or group cohesion; but this is more of a conservative wet-dream, where being different is weeded out or discouraged and one unifying message, culture, or ideology is pushed on the people. Places like Japan, Russia, North Korea, China, Belarus, and India have low homicides by firearm rates. For example, here's Japan -
https://knoema.com/atlas/Japan/Homicides-by-firearm-rate with a rate of 0.0. And US has 3.4
https://knoema.com/atlas/United-States-of-America/Homicides-by-firearm-rate and Belarus has 0.2. The low numbers have a very low number of guns in the population.
https://en.wikipedia.org/wiki/Estimated_number_of_civilian_guns_per_capita_by_country
For example, Belarus is 6.1 and the us is 120.5 and of course the homicide rate in the US is much higher compared to Belarus. But these countries are usually considered very authoritarian (you can't look into it if you want, maybe I'm wrong here).
2. If you let people have guns, but you set out to make a culture that respects them and aims at making people responsible gun owners, gun homicides don't go up as much, but they still go up. Case in point, Sweden (
https://knoema.com/atlas/Sweden/Homicides-by-firearm-rate) at 0.4, with almost 1 in 4 citizens owning a gun is very low compared to the US rate of 125 guns per 100 people and having a score of 3.4. But still higher than Japan at 0.0, which has 0.3 guns per 100 people (or 1 in 300 have a gun). Mathematically if you scaled sweden to the same number of guns as the USA, you would get 2.0 compared to 3.4 of the US, which is still substantially lower (though in this vein having more guns shouldn't necessarily mean a higher homicide rate by firearm in Sweden, since clearly Sweden's gun culture does better than other countries with the same number of guns, so I'm assuming the worst scaling here and it's still about half the USA rate). Portugal is another country similar to Sweden. But take Jordan with a rate of 18.7 guns per 100 people and a homicide by firearm rate of 0.8 (
https://knoema.com/atlas/Jordan/Homicides-by-firearm-rate), which is double Sweden's 0.4 (and they have less guns...). Jordan has much looser gun requirements compared to Sweden and Portugal, where those two countries seem to impose a culture of respect and responsibility for having a gun. Basically, if you don't create a culture of respect and responsibility around firearms, it seems you will have a lot more firearm incidents.
Although it might seem like common sense, the data seems to suggest that you want gun owners to realize they have a responsibility to use them appropriately. Basically, the opposite of USA gun culture (and I know because I am a US citizen, been in the military, and own assault weapons, including a scar 20s and soon a 50 cal). It's surprising how easy it is to get a gun in the USA and how little people care. I have literally purchased and picked up an assault weapon after about a ten minute FBI background check because I carry a concealed carry permit, whereas people that don't carry the permit have to wait three days. But getting the permit is the same requirement for a background check, so people just get the permits so they don't have to wait when they buy guns. I don't even conceal carry and nobody questioned me on why I wanted one. And clearly I'm not using it for its intended purpose.