As an Australian, I always find it odd when US gun people tell me that gun control hasn’t worked here. It is, oddly enough, just factually untrue.
There is pretty solid evidence that after Australia tightened its legislation around guns in 1996, the total gun death rate declined, the gun homicide rate declined, and the total homicide rate declined as well. There was a small increase in homicides in the 2 years after the legislation came into force, but by and large in the two decades since the laws have been amazingly effective.
And, of course, the mass shootings stopped. Not reduced. Stopped. There hasn’t been a mass shooting in Australia since the 1996 Port Arthur massacre. Pretty successful, wouldn’t you say?
The UK is a bit more complex. Their two sweeping firearms legislative acts were in the late 80s and early 90s, when the homicide rate was actually increasing. It’s a bit harder to tell whether the gun legislation prevented homicides when the rate is already trending upwards. That being said, they do enjoy one of the lowest total homicide rates in the developed world, less than one-fifth of the American rate, so arguing that their legislation is somehow ineffective seems a bit disingenuous.
This trend repeats itself across the world. If you map gun ownership and murder rates you tend to see a very strong trend towards more murders when there are more guns. It’s not definitively causative — obviously, there are a lot of factors in murder rates — but the idea that people substitute gun murders for other kinds of murder such as knife, fire, rock etc is largely unsubstantiated.
Basically, gun control works. You see fewer deaths, fewer murders, and perhaps more importantly for this particular argument, it prevents school shootings. Neither Australia nor the UK has seen a single school shooting since their gun control acts, and there has only been a single mass shooting in the UK in the last 2 decades.
If you want to prevent incidents like this happening again, it’s pretty clear what works.