I'd assume that bullets can travel a helluva lot faster than magic explosion stuff, and at a much quicker rate to.
A standard SWAT team would probably have been able to do the job more efficiently than Harry and his friends
English
#Offtopic
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Because Harry Potter can't get his hands on a gun in the magic world because they don't have advance technology nor in the muggle world because it's England and you can't get guns easily in England