Non je suis pas sur.
J´ai rien compris a la formule mathematique pour la vitesse alors jeme contente de prendre les resultats que je trouve ici et la.
Ce que j´ai compris est que le systeme le + simple pour calculer sa vitesse et de prendre un chrono et de vide un carquois de 250 carreaux et de faire des comparaison.

Moi j´ai mis 45\% dans un casque je sais pas trop si ca change
Voici un post du 11dec :
question : max ias for buriza
buriza = crossbow (ballista) with WSM 10.
amazons use crossbows at base 19 frames.
buriza has in-build 80\% IAS.
at 80\% IAS, a WSM 10 crossbow is shooting at 14 fps.
with another 20\% IAS, you get 13 fps.
another 40\% on top of that and you get 12 fps.
then you need another 80\% to reach 11 fps, and that´s as fast as the buriza will ever go.
you need a total of 220\% IAS including the on-weapon 80\% to reach the max speed
IAS isn´t really capped, it´s the EIAS that´s capped at 75\%
if you click the "attack speed" link under "statistics" in the top bar, you can use the calculator yourself to find out how much IAS will create an #fps attack. just remember the WSM is the unmodified base weapon speed, and nothing can change this, EVER. a shael in the weapon counts as 20\% IAS, NOT -20 to the base weapon speed.
Voila
C´est simple non?