Im 90% sure the ladies there have no idea what they are doing, and the same at the Coles I visited the other day.. I think this because it costed me $11.70 for the bottle.. Im prrreetttyy sure thats just the refill price, and there is a "User Licence Certificate" on the bottle which is supposed to be pulled off and attached to your receipt when you purchase it.. On the certificate it says there is a user licence fee of $28.90.. So I thinks I got a bargain...
Anybody in Brisbane who wants cheap CO2 bottles, go to Buranda Woolworths or Fairfield Coles. Or try out your local, they might be silly too

Iv attached a whole bunch of pics of the thread etc so you all can have a looksie and maybe someone will know what it is, and whether it will fit this:
http://cgi.ebay.com/UP-Co2-Plant-Aquari ... 652wt_1008
As you can see inside the thread, there is a pin valve, but it also looks like this pin valve can be screwed out.. If its possible, I could empty the bottle (I have no idea how yet, ideas?) screw out the pin valve, throw the reg on there, and fill up via the reg output, and adjust it to 0 output when its full. Then it can be disconnected, attached to the gun and adjusted again to the required output..
So for now I just need to figure out how to let out the CO2 without it resulting in the bottle punching a hole in the wall of my house.. Ideas on this would be great.
Pics: