Here's how it's currently looking:
Compared to the mk1:
It's based around a plunger tube of .75" PVC, with a barrel of 17/32" brass (nested in the PVC). I finally found a slip fitting for .75" to .5", so I was able to shorten the overall length by removing the male/female threaded parts I had to use before.
The internals. The old plunger shaft was a wood dowel, with the plunger head screwed into one end, knob in the other. Firing pin catchface was a ground down ring of .5" PVC. I've replaced the dowel with aluminum:
Before, I had some CPVC nested under the PVC, pinned with a nail through the dowel. This time, I wrapped electrical tape around the shaft so the catchface fit snugly. The spring uses the tape as a stop. It's worked well so far. The notch is cut out of the endcap because the mini clothespin is so far back, it's under the handle. I had cut the notch before I realized I could trim the pin enough. Oh well.
Here's a detail of the plunger head:
I found a handy part...an expansion nut. Essentially a rubber tube with a nut at the end of it. Tighten the screw and it bunches up the tube, wedging it inside the tube. That's what's holding the plunger gasket on. I just put a washer on top, then my usual rubber gasket and finishing washer (same as on the SNAP-1 mk2). I can't find a washer small enough to fit well in .75", so I trimmed one down.
The plunger works well. I want to try out a full size versionin the SNAP-1, as I think it would reduce weight and length even further; cut off the back .25" of an endcap for a catchface, and then mount the plunger gasket directly in front. My old plunger length was about three inches after the end of the spring. This design could remove 75% of that length, and allow for a gun that much shorter.
Current trigger is a mini clothespin, backwards, mounted under the handle. The metal I'm using is way too soft right now, so the trigger has less than a solid pull. Sort of boingy, really. Not good, at any rate. It also doesn't help that the placement of the pin makes for more of a down trigger pull than back.
I haven't done extensive range testing at all, but it seems to be getting around 50' or so.
Edited by Carbon, 18 May 2007 - 11:32 AM.