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The Snap-1s

With a new plunger style

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#1 Carbon



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Posted 04 April 2006 - 09:57 PM

I figured that since this gun only ever got one picture in the homebrew gun thread (and since I finally redid the internals), that I'd post about it. It's the SNAP-1s mk2, as it follows the general design of the SNAP-1 (rear pull plunger), and is the second version. S still stands for sidearm.

Here's how it's currently looking:
Posted Image

Compared to the mk1:
Posted Image

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:
Posted Image

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:
Posted Image

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.

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#2 fobpawwor



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Posted 04 April 2006 - 10:38 PM

Nice, its like the SNAP's little brother. Love the simplicity and design. Also, your plunger lost some extra grams, so nice work. Another thing is that your barrel looks like its sagging down, but that just may be the picture. Overall, great job!
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#3 boltsniper



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Posted 06 April 2006 - 12:31 AM

That plunger assembly is just sexy looking. What spring are you using and where are you getting them? You got a handy little pistol there. Very nice!
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