Plumbata

[ambrosius]

When you pass them forward to the front rank you can pass the bucket in one go, rather than passing one dart at a time.

I still think that throwing them from the front is possible, but that this can be done only when a) the fight is still some time away and b) when you have ample space behind you. But it's possible.
I think that it were the back files that threw plumbatae over the heads of their comrades when these had become engaged in earnest.

I'd have to agree with you there, Robert (is this a first hock: ).
Once the front ranks have closed, your own men will be poking
the enemy away with spear or sword from behind a shield wall.
But your back rankers are not only free to rain plumbatae down
on the enemy (their back ranks, at least) but they will have the
room to swing the plumbatae as much as they want, since they
don't have to worry about poking their own men in the eye. They
are in the ideal position to swing plumbatae in an arc over their
own men's heads and onto the enemy's middle and back ranks,
causing disruption to the 'push of pike' of the enemy and making
it easier for you own front rankers to push them backwards.

Ambrosius/Mike