From an external point of view, I'd say you / we need to find a way to redirect the attention of arms manufacturers, from being driven to produce weapons for profit.
As long as you have armies of shareholders depending on profit from arms sales, the pressure to lobby is enormous.
It could maybe be defused by a substantial, unconditional UBI, as would be pretty much all crime.
My own stories focus on how and why this should be made to happen, and actually nature appears to be insisting, by progressively devaluing money issued as debt, which can only enumerate business which is dependent on energy extracted from Earth.
Money has to be issued for free to enumerate and monetise the economic product created from solar, and solar is already about 20 percent established, in the form of domestic and community solar installations, so ignored by utilities energy companies, who's business is being lost to it.
Issue the free money reflecting creation of free product from free energy, and the problem of gun control might be fixed, I think.