5/5 turn three

[MementoMori]

You're not casting a spell when you bloodrush. It won't trigger heroic.

Bloodrush is clearly an activated ability. Compare it to overload or bestow; both of those mechanics use the word "cast" in their text. Bloodrush is written as "[Cost]: [Effect]" and makes no mention of casting.

[griffin131]

1: Forest, {avacyn's pilgrim}.
2: Plains, {phalanx leader}, Rush {Slaughterhorn} on leader.
  Pilgrim is now 2/2 and the leader is 5/4 until end of turn, though neither can attack yet.
3: Land, {common bond}.
  Depending on multi target ruling, Pilgrim is a 4/4 & leader is a 6/6! Or u have the turn 3 5/5 with a 3/3 to accompany. Of course, a pair of growths in your hand instead of common bond would do even better, but as its selesnya that's where I'd want {advent of the wurm} instead for an even more threatening turn 4!

bloodrush doesn't target

It really does. "Target attacking creature..."

on another thread. Someone said it wouldn't work with heroic

It doesn't work because Bloodrush isn't casting a spell. Bloodrush definitely targets.

[Steerpike]

Ah, found it on mtgsalvation (i assume that's reliable)

"Heroic abilities trigger only once per spell, even if that spell targets the creature with the heroic ability multiple times"

[Birdbrain]

Ah, found it on mtgsalvation (i assume that's reliable)

"Heroic abilities trigger only once per spell, even if that spell targets the creature with the heroic ability multiple times"

what about replicate? Technically with replicate your casting a whole new spell

[Agrus Kos, Enforcer of Truth]

Turn 4 9/9...drop a {Heroes' Reunion} with a {Voracious Wurm}. If you put down a mana dork on T1 or T2 you could do it turn 3.

[Flashley_ska]

Replicate, and similar effects that say copy target spell copy it on the stack, so don't "cast" the copy.
If instead an effect says to copy target card(ref. {elite arcanist}) then cast the copy, you're good.

[Flashley_ska]

As far as I can tell, yes.