Training with crossbows appears to be broken (melee, not ranged).
Several saves to determine cause of crossbow training problem.

Basic: Basic embark, two dwarves assigned to the military.
t0: No weapons
t1: Training swords
t2: Crossbows and quiver, no ammo
t3: Crossbows, no quiver.
t4: Crossbows, quiver, and ammo
t5: Training sword and crossbow, quiver, ammo.