I got this blaster as a freebie from Chili when I bought
this.
Here is an overall picture; it's actually the final "finished" pic as well; I forgot to take a pic before taking it apart.

First thing's first: remove the water reservoir. I find it helps to slide it "back" a little first, then pull it off from the right side.

Remove the screws and you'll see this:

Hmm, not looking good...

I continued, though, cutting off most of the peg...

...and wrapping the remainder in some e-tape.

I cut a CPVC barrel as short as the stock, orange "barrel" and wrapped it in some e-tape to seal with that orange barrel.

I put it in the orange barrel.

And reassembled it (which is a pain thanks to the water parts). Final pic (as seen above):

Results: a tight dart traveled about 5 feet, and a loose dart didn't even leave the barrel.
But it's still a cool water squirter!