Gallo's page

And what you highlight is that yes, it is too difficult to wield to be used efficiently on the battlefield. Which is why it was eliminated from armies since antiquity.

Slings were widely used up until the same time bows went out of use. They just have less of a presence in the records. One of the reasons I suspect there is little reference to them, for example in paintings, is that they were looked down upon as peasant weapons (even more than bows were looked down upon by knights and the like).

The Aztecs used them, so did various Pacific Island cultures and many Native American nations too. One interesting things is that rarely was there an overlap. There are few examples of cultures using both bow and sling as weapons of war.

One of the problems with the sling is that it takes a more room to wield (depending on which style of slinging you use - underhand, overhead or the "throw"). This is illustrated in a battle scene from the recent movie Alexander. The Persian bowmen are lined up virtually shoulder to shoulder firing away. Then you see a Greek slinger race out from between two phalanxes are fire a bullet at a charioteer (iirc). Whirling a sling takes up more room so it is harder to get the density of fire that you could with even realtively untrained bowmen standing close together.

Every herdsman from Iberia to China used them when herding their flocks, herds, etc., which implies that any Tom, Dick, or Harry was proficient, or could be proficient, with no military or official training at all.

Just because anyone could be proficient does not mean everyone is proficient. It's all about how much you practice and the average person would not have much time unless they had a compelling reason to do so.

According to some historical sources all Roman legionaries received training with the sling (normal sling or staff-sling). Now their skill levels would vary and at the least would be sufficient to put down a volume of surpressing fire when used enmasse. But to be able to hit an individual target (which is essentially what the D&D combat rules cover), you need to be far more proficient.

A sling bullet - for example one made of lead - is quite pointy and when launched would spin and have considerable penetrative power. Armour wouldn't completely negate the impact of a lead bullet. Damage is not solely reliant on penetrative power - otherwise everyone would use spears and maces would be relegated to cracking walnuts. Short of being clad in full plate much of a soldier's body would be exposed - lower legs, feet, arms, face etc even when wearing armour that by D&D rules has a high protective value. Sling bullets have been shown in historical references to hit a metal helmet and kill the wearer.

The round bullets in some historical references are more likely to be large stones fired from a staff-sling which had a shorter range but higher trajectory and were ideal for lobbing stones, and other items over walls of towns.

I think the rules - both Pathfinder and previous D&D variants - undersell both the damaging power and difficulty of use of the sling.

Historically sling bullets (lead or clay/ceramic) had a greater range and more pentrative power than arrows from simple bows (a short bow in D&D rules). There are various reference for this - try www.slinging.org

Plus the sling is not a "simple" weapon - it takes a lot of practice to be proficient. It should be a martial weapon. At least with a short bow (a martial weapon) you can point in the right direction and hope for the best. With a sling you need to have far more trainig to make sure the bullet heads in the right direction (and not sidewards or backwards!)

So I suggest - as I use in my own "house rules" - that the sling be a martial weapon. Damage using a sling bullet should be 1d4 / 1d6 and range increment 60ft. Damage using a stone should be 1d3/1d4 and range say 40ft.

Then there is the whole damage/range issue of using larger stones - baseball sized - that would have a shorter range if thrown from a hand sling (one with the the appropriately sized "cup") but a longer range if thrown from a staff-sling.