At level six the sohei can gain weapon training in the crossbow or thrown weapons group, and the ability to flurry with those weapons.
Crossbows and sling-type weapons generally cannot make multiple attacks per round without special feats.
Does the sohei ability to flurry with them trump those requirements, or does he require rapid reload or ammo drop+juggle ammo?
Light crossbow with rapid reload. Sling with halfling stuff..