johan wrote on Nov 29^th, 2017 at 12:57pm:

Thanks for the advice. I very very very rarely sling pirouette style, so it's far from perfect. But I did notice, that I'll have to just turn my body ,and keep my arm almost straight, slightly bent, and not try to throw in the end. Otherwise, it was harsh on my muscles. I would guesstimate that the over half a kilo ball was pulling 20-30kilograms at least on my arm. Perhaps more. it was pulling my body, when my feet weren't on the ground for a split second.
But it really helps to get some feedback from you guys. From Timpa also. It confirms my initial not so clear experience,and I'll pay attention to this next time.

Yep! An old hut. And we'll demolish it with slings and large stones, ball bearings, bricks, etc.