All numbers from GTH T3 training hall, but the results are similar in the clockworks too.

Volcanic Pepperbox (T3 moderate fire): 66 per tick
Ash of Agni (T3 minor fire): 60 per tick
Firecracker (T1 moderate fire): 19 per tick
Firo Driver (supposed to be T3 moderate fire): 16 per tick

It's not consistent. The big ricochets from the charge attack get 66 per tick like they're supposed to, but the regular shots, the ricochets of the regular shots, the ricochets from the ricochets from the charge attack, and the charge attack itself appears to be T1 minor fire.