I made one with directions that were on a site by "Colin in Ottawa", not sure if he's still on the board.
I used a steel sectioned cleaning rod with some shrink tubing along the joints to help in keeping the rod from touching the barrel and a rubber stopper on the end to seal the chamber ( if it's a semi, don't forget to plug the gas vent with a toothpick or something).
One electrical lead goes to the batteries (I forget which one + or - and I'm not going to dig it out right now) the other goes from the batteries ( 2 D cells) to the barrel/reciever.
You could use the Outers solution, but I just used ammonia. It did remove copper from the bore and placed it on the "electrode" as the Outers system does, and there was no damage to the bore (I olied the crap out of it once I swabbed it clean). I didn't try the Outers lead out solution but I don't see why it wouldn't work.
YMMV