[HPforGrownups] How is it that Wormtail and others can use other's wands?

[Bart Lidofsky]

No: HPFGUIDX 147777

fuzz876i wrote:
> What I want to know is this:  how is it possible to use someone 
> else's wand when that wand is supposed to be specific to the owner 
> and backfire if someone else uses it?

Bart:
I don't believe it says that anywhere in the canon. The only example I 
saw was when Lockhart used Ron's BROKEN wand, which often backfired on Ron.

	Bart