Today's physics question is brought to you via the Russian self defence firearm carried into space. The TP-82 is basically a sawn off shotgun with a 3rd rifle barrel, and a butt that can be converted into a shovel or machete. It's there in the landing module to help you survive an attack from Siberian bears and to kill an Elk to eat when you land 500 miles off course.
In the comments was this: EVA on the ISS for no other reason that to blast skeets in low earth orbit
So let's get all XKCD about this. You're on an EVA untethered, and wearing your Astronaut Maneuvering Unit (AMU). The Clay Pigeon Launcher MkIV on the ISS launches a target for you. You give it both barrels of your TP-82 sawn off shotgun. What happens next? And where do the pellets and the cloud of clay pigeon fragments end up? More to the point, where do you end up!?!
http://io9.com/did-you-know-soviet-cosmonauts-carried-a-bear-killing-s-1684410938
As for what happens to you- well, the reaction from the shot will start you spinning. Assuming that you have some sort of personal reaction control system, you may be able to recover from this spin, or maybe not. Even the EMU doesn't have much available delta-V.
A shotgun slug has a mass of about 25 grams, and the pellets from a shell are about the same. So the momentum imparted is 25/1000 * 360 = 9 kg m/s. An astronaut in an EVA suit masses about 200 kg; she only accelerates by about 0.045 m/s after firing the weapon.
Dealing with the spin might well be where the skill ends up. Or maybe that's what the second barrel is for.
Or read this: http://en.wikipedia.org/wiki/Orbit
Please do not take offence to this. I am just correcting the misconceptions you hold in regards to orbits.