this is an attempt to post a piucture of a netted pouch

  This particular sling has never been used.  I tried to pull the knots tight to reduce stretching.  The braided nylon cord I used might stretch.  The jute netted sling that Willeke posted in another thread has not stretched at all.  Tony

How big is the pouch? It looks quite big to me and I wonder wether the stones might get trapped in the net or even fall through the holes. But then it would probably work fine for balls.

Funslinger,
  Much nylon twine is very slippery and not suitable for netting.  IMHO braided twine is better in this respect than twisted twine.  You mught also look into bonded nylon twine.  It is specially treated for knot holding qualities  Another problem with knots that slip is that they are improperly tied. I have written net making instructions that show how to avoid this problem.  They can be found at:
http://www.bushcraftliving.com/downloads
Tony

Dravonk,
  Your response prompted me to make a much smaller mesh net.  Because of the small mesh (1/4")when the end loops are gathered to tie on the cords, the cup that is formed that is more pronounced than in the larger size.  Thanks. Tony

Tony,
I followed that link, but you have to be a member of the site to download it.
And no way to see it on the site either. (And I am not going to register at all sites just to see the instructions.)

Willeke

Willeke,
 Didn't realize that Willeke.  The instructions can also be found at:
http://wedcraft.com/netting.html
under "Other Documents"
Dravonk,
I did not notice any difference in slinging a golf ball.  I do prefer the smaller size mesh because it will hold smaller size projectiles. Thank you for the question. 
Tony