Uh, no it’s not. You think they happen less often in Russia? Syria? Venezuela?
"Mass Shootings", yes. "Shoot outs", no.
Venezuela, most shooting homicides are to cover up a crime, such as petty theft. These are inherently not "mass".
Syria is in active civil war, these are not "mass shootings" as much as battles. They're also more shootings to achieve a political end (not to create terror towards a political end) or for the personal vendettas of the shooter.