HorusMaster said: "but before it is sent to the graveyard, it's effect activates" Technically, it triggers, but waits to activate until the current chain resolves. It still activates on the Field, where it was triggered, but we must be careful to draw a distinction between an effect triggering and its activation, as well as its resolution.
krishna said: "If blast with chain is destroyed while Macro or a Banisher is on the field, and it's removed from play, it's effect is still activated right? It doesn't say that it needs to go to the gy." This is correct.
cuzwbd: The damage calculation portion of the damage step does not work like a chain. you have the damage calculation, then apply damage (wherein monsters are considered "destroyed" and Life Points are reduced). As you are calculating damage, BWC gets equiped, then destroyed, triggering it's effect, then, still before the application of damage, BWC's effect activates and resolves, destroying the attacking Monster, at whioch point, no damage is dealt, because the Monster that would be doing damage is no longer alive.