Questions for JKR

[Dana]

No: HPFGUIDX 173133

Dung:
No, I meant in the duel at the end. Harry blocked Voldy's Ak with an
Expelliarmus, whereas he didn't try to defend himself in the forest.
1. AK is meant to be unblockable
2. Harry blocked it
3. Which of the two plot devices allowed that? (Seems to me one of
them is superfluous.)

Dana:
I'll give it a shot in trying to answer this question.

First Harry was not suppossed to fight LV in the forest so the AK 
there could "kill" him. Very simple very clean cut. 

In the dual Harry explains to Voldemort that the Elder wand is not 
his (LV) but actually belonged to Harry himself.
The wand Harry is holding is also his as Olivander told him at Bill's 
house that the wand he took van Draco would choose to serve him. So 
the two wands both belonging to Harry would not duel each other 
because a master of the wand can't be taken out by his own wand (well 
unless you are Lockhart and use a broken wand).
So what you actually saw was a reduced version of the brother wand 
thingy in GoF where AK and EX connected. In this case Harry himself, 
unlike LV, is holding a wand that is rightfully his and therefore his 
spell is stronger then the AK comming out of LV's wand. 

JMHO

Dana