The subject matters in your class sound very fasciating.
Most people don't have any idea about how much damage a sling can cause.
I've got another picture showing the effect of a sling impact.
This used to be an old kitchen table top.
My shot was fired with a normal hand sling at 50 m.
The projectiles were stones (of which one is still stuck), but also concrete balls.
The stones and the balls had a weight of appr. 200-250 grs.
I also have other pictures of me in my historical garment.
They show me shooting "Jaegoor" style.