Since the UK banned ownership of all high powered weapons and handguns back in 1996 there have been NO school shootings.
There’s an efficacy issue here. The guns already exist. A ban does not magically evaporate all the guns. And to get the US down to guns/cap levels of England, you’d have to collect (somehow) 98% of the guns here. In a country in which 40% of the guns in the entire world are in the hands of US citizens.
The Magic Gun Evaporation Fairy
Three Reasons Why Gun Ownership Rates From Other Countries Don’t Matter
You’re talking about magically evaporating 39% of the firearms on the entire planet. How?