Grape shot was some nasty stuff and caused terrible wounds.
72 cal round lead balls shot from a cannon will cause a variety of damage to the human body.
But ... on those riots - those were quelled PDQ. And that was the object of the exercise.
Here’s a vid of modern grapeshot fired from a 120mm tank shell. 1100 tungsten balls at 10mm in size.
http://www.youtube.com/watch?v=Cgn1nhUEgo8