I'm feeling like shit, but I thought I'd post this up. This is the first part of my overhaul that I've been talking about.
To start, I wanted to replace the puny plunger tube, that could only fit a firefly spring.
I had a lot of ideas, and I wanted to push the boundaries on how much volume I could make it. Since the gun is automatic driven by a gear train, the plunger travel distance has to stay the same, so in order to increase volume, the plunger tube had to be of high diameter.
Measuring out the internals, I could fit up to a 3" diameter tube in there, which, when combined with the plunger stroke of ~2", gives as much volume as a longshot plunger tube (stroke of 4"). This however, proved to be not easily feasible.
Searching through my box of random supplies, I found one of my older ideas. Using empty caulk tubes as plunger tubes, and the slider as the plunger head. The slider on the inside makes the most perfect seal (think 1.5" neoprene washer in a LS plunger tube <- props for that one Slug), because it can't let any caulk through (or the caulk gun wouldn't work). These tubes are cheap, like $2 each, and I'm sure any construction site that has them won't mind giving you some. I happened to have had 6 or so.
Anyway, the best combination I found for making my plunger head with the Vulcan plunger head was this:
1/2" wood screw (mine came with a "middle hinge" from home depot)
1 1/2" x 1/4" fender washer
Vulcan plunger head
You need to clamp and pre-drill the Vulcan head as centered as possible. Also pre-drill the center of the slider. I used a 3/32" bit; I would recommend using that or smaller.
Here it is assembled:
With this new plunger head you can now use significantly larger springs. I currently have a Longshot spring on here, with about 2 coils cut off.
This also allows you to combine springs. You could fit a BBB spring inside of the LS spring, and still have room for both a Manta ray spring and a Firefly spring with the Vulcan spring. That of course would destroy your gun in a heartbeat, but I just want you to see how versatile this is now.
I had to cut down a significant portion of the plunger tube holder. If you are repeating this, you will also need to remove both the Sealing mechanism and the manual cocking mechanism. Cut carefully, and be sure not to impede on where the rotation arm mechanism goes. (See the Labeled Vulcan Internals for reference)
Important: Look at my finished plunger tube. This is the top of the tube. In order to get this piece, cut off the tip about halfway down (the more conservatively done the better; you can cut more off later), and push the slider out with something long and thin. I used a threaded rod. Rinse out the plunger tube and slider with hot water.
Also, look right behind where the plunger tube is. When cutting to make space for the tube, be sure to leave that lip there. That, and a similar piece on the other side, keep the tube in place. Without it, the tube will move with the plunger, because the seal is so perfect, and no air will be moved (making the blaster a dud).
On there is a 1" piece of 19/32" brass, and inside it is a 9/16" piece. I have yet to determine the best barrel length.
You will need to cut down this nub on the top half's shell to allow it to fit over the new plunger tube.
Overall, the plunger tube inside diameter went from about 3/4" to 1 3/4" (233% increase), the spring became triply as powerful, and the seal became perfect enough to be able to stop the plunger with ease.
Thus concludes part one.
Edited by Splitlip, 09 September 2008 - 12:08 PM.