Using 'Thunder Clap' consumes ranged ammo that is currently equipped in the character card. You also sometimes gain weapon skills for the currently equipped ranged weapon as if it was actually fired (no firing animations or sounds are played).
This is baseline behaviour not caused by any talent choices.
Confirming this. Loaded up a warrior, added ammo, used Thunder Clap and saw the ammo count go down. I noticed the ammo count does not go down if the ranged weapon is unequipped.
Using 'Thunder Clap' consumes ranged ammo that is currently equipped in the character card. You also sometimes gain weapon skills for the currently equipped ranged weapon as if it was actually fired (no firing animations or sounds are played).
This is baseline behaviour not caused by any talent choices.