So with all this talk of light infantry dueling why am I hearing so little about slingers in light armor? The thick felt, layered jack/gambeson, leather lamellar, etc.? These all sound like they would be of major benefit to slingers at risk of being hit by enemy slingers or javelin throwers, but mostly enemy archers... also the ability to use a shield while slinging is one of the sling's greatest advantages over the bow (and crossbow) and I'm hearing little about that as well. True it does slow your reload rate a bit, but is well worth it.

Also I am aware of a specific culture who does in fact utilize slinging from the rear. The Tribes of the Gilbert island did this and specifically built big back plates into their armor to protect them from the rear slingers in the case of misfire.  http://www.flickriver.com/photos/mharrsch/1443832609/

Also... the term "FIRE" is anachronistic... it comes from adding fire to a cannon or hand gun in the age of gunpowder... a pregunpowder culture would have no idea what yelling "FIRE" meant. Shoot, loose, sling, throw, or launch would be more appropriate.

Also what about multipurpose units... like heavy infantrymen who spread out a bit and plant their spears and sling as the enemy marches up and then once range is closed they pocket their slings, condense, and ready their spears?

Also why is it that the more I read about slinging in battles... and hunting, and pretty much every other situation... overhand and figure 8 seem to dominate while the helicopter sidearm casts seem to be a bad idea. Takes too much space for mass battles (and extra time), startles animals for hunting, gives away position and intent to single targets, less accurate, more difficult... seriously, this cast just seems to look cool (though not quite as cool as figure 8) and be good for slinging at a shallow but wide oncoming line of troops too far for overhand targeting but too close for long range figure 8 bombarding. Anyone want to stick up for this cast?

I dispute that slingers have to be spread out. I was sandwiched between two archers in a speed shoot-off. They were standing two paces to either side of me. I used the vertical Greek style and and shot faster than both of them with no interference problems.

See how little room is needed side-to side here: http://www.youtube.com/watch?v=lJjXXnDSB4s