Okay, so maybe, as we all originally assumed, the Assyrian who engraved the picture was just a lousy artist, but Toli sticks ALSO show what looks like a "SPLIT" a few inches up from the loop, because it is made from one piece of white oak, soaked until the end is soft, and then bent around to form a loop, and then tied over back on itself to the shaft portion of the stick, which makes it suspiciously like the Assyrian picture, and, lest you think you are talking to an inexperienced amateur, or whatever (ACTUALLY, you ARE, but... ;->, heh, heh! IRONY METER DANGEROUSLY HIGH!)
, please note that the overhand cast would be a TERRIBLE choice of techniques for a short, flexible sling as shown for long-range massed use, and a late release here and there would eventually fatally bean several archers over time. However, using a stick rock thrower this way wouild be the most effective way (in fact, the ONLY way) to launch rocks a maximal distance in such a formation. In answer to the weight question, rocks or bullets thrown at long ranges are NOT typically heavier than balls used for sport
Baseballs, for example, weigh five ounces. Toli balls, are a little lighter, but, then, so are 1-3 ounce glandes.
If Lobohunter uses long-tailed, wrap-around slings, that's good enough for me that they work, so, perhaps that IS what the "artist" is depicting. Personally, I think Johnny is a lot better artist, though!