In the US there is the example of Korean shopkeepers defending their businesses from the Rodney King rioters (I think that was the event) using AR-15 so-called "assault rifles" from the rooftops.

They were successful until the police came and made them give up their guns and leave.

Then their unguarded shops were burned.

Col. Jeff Cooper suggested that sniping the instigators with .22LR ammo would be a way of taking the steam out of the crowd. (arguing that shooting them with a .22 will shut them down and give enough time to get them to hospital to save their lives)

Seems to me that preserving the lives of firebombing rioters is over rated.