Why do you care so much about school shootings specifically? Shouldn’t be the goal to reduce overall child mortality? In which case it doesn’t make sense to focus on school shootings. They’re a rounding error in child mortality. Compare actual death rates between first-world countries to see what I mean; the US lags behind its Western peers, but the presence of school shootings, which is generally referred to as a decidedly American problem, is not nearly large enough to make an appreciable difference [1].

[1]: https://ourworldindata.org/grapher/youth-mortality-rate