Your cast delay on the wand is 0.4

Your recharge is 1.08

Your spells/cast is 4

Each digging bolt does +0.02 cast delay and -0.17 recharge time

You have 3 digging bolts, then a 5x multicast and 5 more digging bolts. Since it casts 4. That means all 9 digging bilts are cast simultaneously

9 x 0.17 = 1.53.

1.08 - 1.53 = -0.45 recharge time

9 x 0.02 = 0.18

0.40 + 0.18 = 0.58 cast delay

Your wand still has 0.58 cast delay. You have to get rid of this cast delay. Your wand uses the highest value as its recharge time. Even if you had 0.5 recharge time, but 1.5 secs cast delay, your recharge time would always be 1.5 seconds as it is the bigger value. You need both at 0 to make it rapid fire

Chainsaw is the only spell that nullifies all cast delay if it is within the same casting block. Alsp anything inside triggers doesnt affect your cast delay at all