It's been discussed about why many of the ancient lead projectiles were flat.
Some suggest they slung multiple shots at once,so in that case they would stay better in the pouch together.
How do flat ones fly because of the spin ?They surely have more penetration than round cross-section ones.They're more like arrowheads.
Could this be the reason why ancients made them?
Were they just molding deficiencies ?
Could flat ones airglide in flight,having a longer range?
There are somewhat flat and really flat ones along with perfectly round cross section ones,which are quite rare.
I believe the almost round ones are just molding imprecisions.
What are your thoughts,experiences with them?
I'll surely be making some tests with flat ones,as they're unknown to me.

They're not flat, they look like footballs (US) or rugby balls (UK). Or did I misunderstand ?

Jaegoor wrote on Sep 1^st, 2011 at 3:37am:

You show me the video of shooting a ball (of your choosing) through a pigs karkass, or some other object with a similar density/structure as a human body, with a sling, and I will believe you.
Until then I say this is absolute nonsense.

Actually, I'm examining a lead glan I've got, and it seems to be oval, but you'd notice it only if you're looking for an oval section.
Unlike Thearos, I haven't handled so many, so take my statement with caution.
Greetings,
Mauro.

With throws that come over the top a backspin is very commonly achieved and this produces lift on the projectile.  Have you ever tried to sling for distance with an underarm throw and noticed how the stones drop so quickly no matter how hard you sling them?  The flatter the stones, the more this is true.  This is because underhanded slinging tends to put a forward spin on the projectile and this causes it to drop quickly like a curve ball.  The rougher or more mis-shapen the surface area, the more the spin on the projectile alters its flight path.

When throwing with a throw that releases in a baseball pitch or higher sidearm type release, lift rather than drop is produced.  The backspin produced often seems to cause enough lift to neutralize the natural trajectory for a good many yards before the drop comes.  Usually the drop comes quickly at the very end of the throw after the stone has sailed out straight for a long ways. 

The same principle is used in airsoft bb guns where there is often an adjustable backspin device placed at the breach end of the barrel which puts backspin on the bb's and causes them to sail out a lot further and straighter than they otherwise would at a relatively low velocity.

I believe this is the reason for the oval cross section in glandes.  Lead is a dense material and it would take something like an oval cross section to produce the desired lift since lead has little surface area to begin with for a given weight. 

I've never done experiments with glandes other than a few fishing weights, but what I've learned from stones gives weight to this theory.  Even the lead fishing weights produce impressive distances!!  But I think one of the main advantages of the sling in ancient times was to rain lead on an approaching troop from as long a distance as possible.  This more than any other factor had to influence their design of the glandes.  If the flat glandes went further even a certain percentage of the time, then that was the potential elimination of an enemy soldier before he even got close to you.

The other thing could be that it was easier to produce oval cross sectional glandes with the types of casting moulds they were using.  If they were chiseling out rock to make the mould, a shallow pocked would have been easier to produce then a deep one. 

     

Backspin is not an issue with these,as it only works for spherical projectiles with success.
But whipartist had a good point about chiseling stone molds,so it would've been easier to carve out a shallow groove than a half round one.Here's a pic of a flat gland.It appears to be about twice as wide as thick:

Those are pretty plump, though, and I would have thought close to round cross-section ?

But if they could carve the bolt and the inscription and have such a nice shape to it,they could surely make it round cross-sectioned.
Flat for not to roll out of the pouch doesn't seem like an issue to me,as round cross-sectioned ones stay in the pouch no problem.
Here's a pic of a flat clay one i've made,that i'll be testing: