Brilliant.
I have four of them.
This is how I use them.
I use them as a fermenter first. (I've got myself an extra four caps with airlocks that I had to make up myself).
When the barrels have stopped bubbling I bottle HALF of it with a spoon full of sugar for each bottle (about twenty bottles for each barrel).
Each barrel is now half full.
This gives me enough dead space inside the barrels to drop around twenty five level table spoons of sugar in.
Then I screw on the lids with the pressure vale on, and then I give it all a couple of weeks. .
Hint: Use vast amounts of vaseline to seal everything up and you cant go wrong.
THE METHOD ABOVE HAS NO NEED OF CO2 BOTTLES