Went to the river yesterday for a bit of slinging.
Cool locale on the riverbank with plenty of stones and free, open space. Unfortunately that particular part of beach had mostly old, rounded pieces of brick or sharp bits of basalt. Not the most amazing ammunition.

Brick isn't really that dense and the basalt was too edgy to have any kind of accuracy at all.

Using my cupped, braided string I averaged about 60m (according to Google Maps) distance using a simple overhand throw without pre-spinning.

Twice I found a good sized, rounded and dense stone which went between 85-100m distance, just over a small mud flat!

Found a weird, light ovoid ?stone? I suppose? It was really light so I think it's actually an old barbecue brick ;D.

Pictures in link below.
http://imgur.com/gallery/Hj7cDqy

On another note, I just can't seem to get the hang of throwing with a pre-spin. Does it actually add range and power or is it mostly for form?

Pre-spins aren't actually necessary. It can help with feeling the weight of the ammo before you throw but on the whole it doesn't add much.

Like Kick mentioned, a pre-spin (rotor) can give you a feel for the weight of your projectile.  Another thing is it puts the projectile in motion, so less energy is needed to get it moving when you go into your throw.

You said you can't get the hang of it.  I think a big part is what feels natural and comfortable for you.  I'm the exact opposite.  I always use a rotor.  I've thrown a little bit without it, but the throw feels rushed and incomplete.

And beautiful looking location you have there!  :)

Nice pics- that stone looked odd- what is it?

CrazyBrave333 wrote on Sep 16^th, 2020 at 11:45pm:

Nice pics- that stone looked odd- what is it?

I actually think it's a water soaked bbq brick  ;D

joe_meadmaker wrote on Sep 16^th, 2020 at 7:58pm:

Like Kick mentioned, a pre-spin (rotor) can give you a feel for the weight of your projectile.  Another thing is it puts the projectile in motion, so less energy is needed to get it moving when you go into your throw. You said you can't get the hang of it.  I think a big part is what feels natural and comfortable for you.  I'm the exact opposite.  I always use a rotor.  I've thrown a little bit without it, but the throw feels rushed and incomplete. And beautiful looking location you have there!  :)

I usually swing it a bit forward underhand before I bring it over my shoulder and throw it. Only way I get actually get any kind of accuracy haha

It’s a conversation for the maths section... but pre-spin stores some energy before the throw. I just started playing with it recently and it also helps index your body position for aiming... plus feeling the weight of the ammo.

   You're getting pretty good distance. Beautiful slinging site.  For my first few months of slinging I also didn't use any pre-spin.  I used just Apache Style, which is OK for certain circumstances but is limited in its range and accuracy.  Using pre-spin just felt awkward to me.  I practiced other styles using pinecones at first so I didn't hurt myself or anyone else.  Eventually I got the hang of it and my overall performance improved. 
   Everyone is different.  There are several styles that don't use pre-spin that are effective.  I would say experiment, learn everything, and retain what works for you.