https://en.wikipedia.org/wiki/Estimated_number_of_civilian_g...

https://en.wikipedia.org/wiki/List_of_countries_by_firearm-r...

Check out both tables and you will see that the facts do not say what you think they say, at all.

Homicide rates by firearm per 100,000 inhabitants (2017):

  Jamaica - 47.857
  United States - 3.342
  Serbia - 0.415

  Jamaica - 8.8
  United States - 120.5
  Serbia - 39.1

It shows that Serbia has loads of guns, yet barely any firearm-related homicides, whereas Jamaica has much less guns, yet homicide rates by firearm are way higher than the US.

Thus, the statement that "More guns -> More gun-related violence" is evidently false.