Harry's protection and Ron's wand (WAS Re: AK and victims' remains)

[justcarol67]

No: HPFGUIDX 91500

Susanne: 
<snip> I always thought the above event [Lockhart's  memory spell
backfiring] had nothing to do with Harry's powers or protection, and
everything with Lockhart using Ron's broken wand, which has been seen
to malfunction in similar ways before. <snip>
 
  
Ravenclaw Bookworm:
<snip>  Susanne, the other times we have  seen Ron's wand misfire, it
usually redirected the spell onto himself - slugs being the most
dramatic example.  It gave Ron trouble, but I don't remember it
causing destruction.
<snip>
> 
Jo Serenadust:
> I actually think that this time, canon is pretty straightforward 
> about the reason the tunnel collapses and Lockhart loses his memory. 
> As Ravenclaw Bookworm said, Ron's wand backfiring hadn't caused 
> destruction before Gilderoy L. used it. However we should remember 
> that Ron had not ever tried to use it in a confined (and unstable?) 
> space before and more importantly, Ron is only a second year wizard 
> with a second-hand wand at the time of the COS events.  Lockhart is 
> a fully trained wizard who, while he may be magically inept at DADA 
> and healing charms, is a master at powerful memory charms.  This 
> fact is the entire justification for his success in taking credit 
> for the accomplishments of many other wizards and witches.  Since he 
> tried to Obliviate both Harry and Ron at once with Ron's feeble, 
> spellotaped wand, I can easily accept that the power of the charm he 
> attempted to cast was enough to result in the tunnel's collapse as 
> well as his near total memory loss.  I just don't think that JKR 
> left much wiggle room here. <snip>

Carol:
Just a small addition to Jo Serenadust's explanation, which I agree
with: Ron's wand backfires against its user, regardless of whether
that person is Ron or someone else. In previous scenes (the slugs, for
example), the user is Ron. In the Chamber of Secrets scene, the user
is Lockhart. So there's no need to bring in a protective charm on
Harry to explain the backfiring (or the collapse of the tunnel, which
Jo has IMO convincingly explained). 

Carol