If you are Moving at the Speed of a Bullet and Shoot it Backwards, What Happens?

Let"s say that you are traveling along at about 300 km/h. For some reason, you decide to do some target shooting in order to pass the time. So you take out your trusty gun, or cannon, or what-have-you, and you point it backwards. In this case, you are firing in the opposite direction that you are traveling (after all, you don’t want to shoot the pilot). As luck would have it, your weapon fires at the exact same speed that you are traveling. So, you are flying along at 300 km/h and you are about to shoot a bullet/cannon/whatever in the opposite direction at 300 km/h.

What happens to the projectile? Does it go shooting off in the opposite direction? Does it go anywhere? It may seem like a silly question, but it is important to any aft firing aircrafts.

Will it shoot backwards at 300 km/h relative to the ground? Will it travel back slowly and then fall down? Find out at:
http://www.fromquarkstoquasars.com/if-you-are-moving-at-the-speed-of-a-bullet-and-shoot-it-backwards-what-happens/

Image source:
Niels Noordhoek / Wikimedia Commons / CC-BY-SA.