Clarification with "The Barber"

Instead of dealing direct damage, your Spirit Barrage now accumulates on the target. When you stop casting, it explodes dealing [400% - 500%] of the accumulated damage to all enemies within 15 yards. (Witch Doctor Only)

All the while, I just took this item for granted and just kept attacking with Spirit Barrage and wait for them to die…

So today as I was doing a GR130 with a freshly built WD. Against the RG (Perendi?), I kept casting and casting… RG’s health barely went down… So I decided to look for any Pylon, stopped casting, moved away then boom RG dead!

I tried again on another RG the same method, but no go. Seems like I am missing a step or something.

I watched Wodijo’s GR150 HC video and he did the same thing: RG ~80% HP then dead!

How do you trigger the “stop casting” part consistently for the massive damage?
Last time I played Mundunugu was so long ago, I forgot the details.

PS: I dont have COE equipped, so it is not about “timed during Cold cycle”.

According to an old thread:

Hmmm… Maybe I accumulated enough “potential damage” and it killed the RG instantly then…

So I should just keep attacking…???

General Spirit Barrage cycle with The Barber is following:

  1. Cast 3 Phantasms without channeling SB.
  2. Start channeling SB to build up “charge”.
  3. Quickly recast the 3 Phantasms to detonate the built up charge.
  4. Repeat.

It’s a mechanic that takes a bit getting used to but once you get the basics, it’ll feel more fluent.