Replace the springs (Catch and Main, trigger seems fine), lube the plunger head and flare it out for a better seal. Ignore the masses of E-Tape, it doesn't work as a cocking device.
Take your coupler and piece of CPVC and hammer it in, then glue the coupler on. Cut the cpvc so the coupler is ahead of the screwhole, and sand it down on the back to the exact length of what remains of the barrel. This way the barrel won't take any of the force of the plunger head.
Then goop and glue it in. Make sure the glue doesn't get in the place where the orange barrel rests on the plastic, and put extra glue on the sides so it fits better in the gun.
Finished product with barrel
I can't find a good cocking mechanism. I've tried E-Tape, wire, keyring, and zippy ties. No of them are very comfortable, except for the E-tape, but that broke off pretty quick.
Ranges are about 60 feet flat, depends on if you use bands.
Update: You can reduce dead space even further by doing the exact same steps with a bit less cpvc so the coupler is directly on the plunger tube by simply putting a little nick in the coupler.
Edited by Blue, 13 October 2009 - 01:36 AM.