DISSECTING THE PLASTIC BARREL
So I got curious about the metal plug inside the plastic barrel and did a little surgery on one that I chopped off for the steel barrel upgrade. First I clamped the barrel in my mill and tried to mill away one side. I discovered that the plug is made of hardened steel and is a separate piece from the little plate in the breech. I then sliced off some more plastic along one side on the band saw. The plug did not appear to the molded in place. It's what you are seeing when you look in either end of the barrel.
http://i1053.photobucket.com/albums...nosuke Blaster Build/CRW_5232_zps81e6c6c7.jpg
I was able to easily pry the plug from the plastic and discovered a small dowel pin that was holding it in place. Also interesting was that the plug was stepped in diameter, larger for a short length at the muzzle end.
http://i1053.photobucket.com/albums...nosuke Blaster Build/CRW_5237_zps67f69dfa.jpg
The dowel pin was held in place in a through hole where the ammo clip bolt attached by a small ball bearing.
http://i1053.photobucket.com/albums...nosuke Blaster Build/CRW_5239_zpse37f5513.jpg
http://i1053.photobucket.com/albums...nosuke Blaster Build/CRW_5241_zpsf2717a34.jpg
Looking at the inside of the plastic barrel you can see the shallow hole into which the dowel pin fit. Note also that the small hole on the side is through threaded, but that there was no corresponding hole in the plug. Meaning that the barrel and frame were molded without the plug in place and that it was added after the holes were threaded.
http://i1053.photobucket.com/albums...nosuke Blaster Build/CRW_5234_zpse5b97381.jpg
Close inspection of the through hole in the plug revealed a little bit of clear residue, probably from a drop of glue used to keep the ball bearing from falling out. In some cases, the ball bearing was loose in the box, having fallen out of the hole.
So this gave me an idea. I put a couple of drops of lacquer thinner in the hole on another intact barrel to soften the glue. (The solvent had no effect at all on the plastic so it's not styrene.) Then I rapped the barrel against my workbench which caused the ball and pin to drop down a bit. I could then easily push the plug out of the barrel with a stiff piece of wire through the breech end. This plastic barrel is going to be replaced with a steal one anyway.
http://i1053.photobucket.com/albums...nosuke Blaster Build/CRW_5227_zpsf4025b02.jpg
Related to this, I was able to remove the metal washer from the cylinder by cutting away the plastic on the front end. I did it on my lathe, but you could do the same thing with a Dremel.
http://i1053.photobucket.com/albums...nosuke Blaster Build/CRW_5242_zps9dfe537c.jpg
http://i1053.photobucket.com/albums...nosuke Blaster Build/CRW_5243_zps9a91ee80.jpg
And while I didn't do it, with a little bit of careful grinding, the zinc plate in the breech could be removed leaving a free and clear open barrel.
What all this means for our members in the U.K. is that if you're a little clever (and very stupid!) with a little bit of work, and using common tools, you could turn the Tomenosuke into a real shooter. Of course the plastic barrel and frame would blow apart with the first shot and shred your hand, but I bet the bullet would come out the end!
DON'T TRY THIS AT HOME KIDS!!!