Response to "Nanab":

Nanab said...

Well, in the original books Seamus didn't really have much of a problem with explosions at all. He was just a minor side-character and honestly, I can't remember too much about him. Any and all references to his ineptitude at wizardry were created by the movies.

Thank you for giving me the opportunity to delve deeper into this issue, Nanab. Although the books seem to be lacking on hard proof, there ARE other indications that Seamus was known for... well, blowing things up.

From the Harry Potter Wikia

Seamus was noted for having a tendency to make things explode, although this was usually unintentional.^[8][9] However, during the Battle of Hogwarts, McGonagall recommended that Seamus aid Neville Longbottom in destroying the Covered Bridge, recognizing that his particular talents would be of use

 And also,

Professor McGonagall: "Why don't you confer with Mr. Finnigan? As I recall, he has a particular proclivity for pyrotechnics." 

Seamus: "I can bring it down!"

And I could be wrong, but I believe at one point there was a comment made by another student about Seamus singeing off his eyebrows on a regular basis.