As well as the Balearic slingers were considered the best ones of the world because they could shoot with accuracy farther and greater stones than anybody, the Achaeans were reputed to even have better accuracy than the Balearics. It was due, aside their ability, to the use of a special sling that allowed the glandes to remain fixed in the pouch and always come out in a precise way, “like the arrow shot by a bow” (Livius)..... Did he means point-first ?
I have not practiced much with glandes, but I have observed what follows with stone projectiles and mainly with clay projectiles, of controlled shape.
If we turn around the sling with a certain separation between the two cords -the retention end in the middle finger by example- and we imagined the position of the pouch throughout a complete horizontal turn, we observed that when it is at our right the projectile is oriented with the point to the front. Therefore, if we let go the cord now, the projectil come out tangent to the circular trajectory, oriented point forward. This is one of the techniques of point-first launching, that nevertheless does not allow us to reach the maximun power as it is developed in a quarter of turn. The maximun power is obtained, as we know, with pitch type baseball launching, prolonging the arm forwards, which has a greater duration and effectiveness of transference of the momentum. Unfortunately then, the position of the pouch makes the projectile to leave crossed forwards. The technique can be varied using for example a vertical turn around and also modifying the position of the hand when releasing so that the projectile come out the best oriented forwards, but always this is obtained at the cost of a lost of power. For that reason we must adopt one or another technique according to the purpose of the shot. If we want to obtain a great penetration at a medium distance, we will use the point-first technique, but if we want to obtain the maximum distance we will forget it.
On the other hand, point-first flight considerably reduces the air resistance, like all we agree, and we would have to consider if this effect compensates the lost of power of a launching point-first. The best thing will be probably a launching tecnique little forced, that provides to the projectile an inclination of about 30 degrees for example. This could be obtained without an appreciable lost of power and the diminution of the air resistance would be interesting. The launching technique would consist then of a turn around inclined 45 degrees and taking some care of the position of the hand in the release.
The shape of the projectile is the other decisive aspect. In my opinion glandes do not orientate by themselves as someones think, I´m sorry. On the contrary, due to the gyroscopic effect they acquire when shot, they roughly conserve the inclination with which they start off, because beeing symmetrical and been their frontal surface symmetrical too in any position in which they fly, the force of the air is applied on the same direction of the center of inertia of his mass. Nevertheless, an asimetrical frontal section is put under a nonbalanced push of the air that rotates the projectile until it is oriented in a position in which this push is balanced. In a projectile with droplet shape which axis is not oriented on the flight direction, the center of the air push on the frontal section is placed towards the tail with respect to the center of inertia and, as I´ve said, a pair of forces takes place that rotates the projectile until both centers are aligned when orienting the projectile with the tail backwards. This effect was already used by the Romans, who reduced lightly the half of the glans.
However, this optimal assymetrical projectile, involves the problem of its lodging in the pouch. In a conventional pouch it would be left some inclined, and in the release it could oscillate and fly in a chaotic way. This takes us to another delicate subject: the design of the pouch. Conventional glandes even can leave oriented in an unpredictable way due to small variations of its position into the pouch when launched. For this reason the achaeans, masters of accuracy, took care so much of the design of the sling, so that the projectile was fitted well in the pouch and it was freed of precise way. I seems to me that the design of the pouch to lodge a type drop projectile placed trasversely, so that it takes spin, would have to offer equal support throughout its logitudinal axis. The transversal section of the pouch wouldl have somehow reproduce the longitudinal profile of the projectile, making the pouch of several sewn parts or by means of splits or holes. This is a good field of experimentation....
What do you think about all this stuff? The subject is very intrincate although exciting, but I think my message has been too long, almost an article, and maybe some confusing or sometimes unntelligible due to my (and altavista) english