I'm from Serbia, after the war there were guns everywhere in all forms. We had among the highest murder rates in the world and we were 2nd in the world just after the US in guns owned / population ( In recorded statistics ). Mass shootings, armed robberies and murders were common place.
In 2003 the Serbian government initiated the project to rid the country of it's post war rampant weapons ownership. Banning almost all form of private ownership with the obvious exceptions. Instead of prison sentences for illegal gun ownership heavy fines we're set with a minimum being 10 000 euros and higher if your income is higher, we have to remember that the average yearly income is around 5000 euros.
The government set up tip hotlines for people to call in if they knew somebody owning a gun illegally. A system was set in place for law inforcement to attain search warrants easily if guns were involved.
Immunity is given for handing in your weapons by calling the police to come and retrieve them, even 15 years later after the start of the initiative.
Today 2018 it is estimated that over 350 000 rifles, assault-rifles and handguns have been siezed and destroyed in a country with 7 million inhabitants.
Our murder rates have dropped by 480% and armed robbery by 350% at the same time we removed the life-sentance penalty and reduced the law inforcement budget by almost 15% ( mainly because of our poor economy ). Ofcourse there are other factors in those stats as the stability rised but it is hard to deny that a tighter control of guns has had a positive effect on our society.
I'm not saying this would work in the US or anything like that, just giving an example of how it worked for us.