here is a picture of the parts. The barrel is about 4 1/2" long and has a 3/4" hole through it. The sound chamber is
2 1/2" long and has about a 1" tenon, it has a 1/2" hole on the tenon end about 1" long, the exhaust end has a 3/4" hole.
I made the 2 plugs out of a 3/4" oak dowel by putting in the collet chuck and drilling a 1/4" hole through it and then parting off two pieces. Make sure you sand the end of one of the pieces before you part it off or you will be parting off 3 pieces.
The call has a double sound chamber the unsanded plug is covered in glue and pushed 1" into the sound chamber and the sanded plug gets glued in flush withe the end.
I don't know if this is how its supposed to be done, but it make owl sounds. It won't win a contest but it sounds owl enough to make a tom talk. I am gonna play around with this some more. I'd like to get it to sound as good as my h.s hoot tube.