In the original book, Smaug is confident that Bilbo is no threat to him, so he tells him where his vulnerable spot is. And Bilbo tells Bard.

"Gandalf" - After receiving your second missive in my inbox on the subject of what I consider to be the "lucky shot" and your reminding me of how Bard found out about the weakness, I suspect that you are simply testing me now after my application to your Order. (I have read the book 3 times and am aware of how Bard finds out about Smaug's weakness - so again, I assume it's a test!)

My defense: Now granted Bard was an EXCELLENT archer, and very, very brave. But as an archer myself and an archery coach for youth, I must bring up the subject of how arrow weight (since the Black Arrow was forged by Thror and would have been made of a metal instead of the usual wooden arrow) affects the flight of an arrow and that a change in usual arrow shaft length (since the Black Arrow had to be quite long to actually affect Smaug) would be a problem for an archer. With your knowledge of physics and trajectories for your lovely fireworks, I'm sure you will agree with me.

Point the First: Arrow weight. The heavier an arrow is, the more force (bow poundage) it requires to fire it and make it stick into the target. Bard shoots a longbow (which historically had a draw weight of about 100 pounds). This would have to be increased quite a bit to make the arrow (now matter how pointy and sharp it is) to actually penetrate dragon hide (even the part without the gem plating). It would also affect how well and how long Bard could hold up the bow at full draw to get a site on the dragon. They do fly fast but an archer has to have control of the bow to track a beast. Assuming you will bring up "What if that the arrow had magical properties (like maybe it was made of Mithril)?", I will proceed to my second point.

Point the Second: Smaug is huge. HUGE! A tiny regular hunting arrow would do very little damage because it could not penetrate deep enough for the needed effect. Many archers use the tip of the arrow as a sighting point - a long arrow would be a problem. Assuming instead that Bard shoots using the instinctive style of shooting, it would still be a problem because the arrow has changed and it's wobbling in flight would be different than what Bard is used to. When changing arrows, it's recommended you practice with them first. Bard would have had little chance to practice with the Black Arrow. (Who wants to advertise they can kill a dragon? It'd be "Come kill this dragon for us!" all the time.)

Thus, I conclude Bard's shot was a lucky shot.

Sincerely,

The ever so humble Order applicant, Cloudlakes

P.S. Did I pass the test?

P.P.S. I really do like your fireworks! :D

In the original book it wasn't a lucky shot. Bilbo learnt where Smaug's weak spot was and told Bard.

Fantastic story I hope you write a sequel where the masters and Sauron make an alliance that places the survival of both worlds at stake. So both have to pool their resources and combine magic and technology to survive. :D

Wow. This was absolutely brilliant! Usually, I look for anything that has Chuck in it, but this one didn't need him to catch my interest. It was very well-written, and introduced two new, heart-warming, spunky characters that made me wish they were in the original storyline, as well as seamlessly tying two very different stories together. Very impressive. :)

cooooooooooooooool!

I thought this crossover was a cool idea, but then you made two mary sueish ocs the center of the plot. This could have been so much more!

LOOOOOOOOOOOOOOOOOOOOOL
So epic :D

I liked this story. IMHO you could write the Smaug part longer, the fight was a bit rushed. Also, the twins fell for Fili and Kili a bit too fast for my taste, but it was fun to read anyway. Just for be an annoyance, the planet is Middle Earth not "midgard", and Jaeger means "Hunter" not monster. And last... Saruman or Sauron would die to know how to build a Jeager himself! You could write a sequel (with more giant robot battle?).