Update – 1/5/11 – Photos of the new proof of concept at the bottom of this post.

I’ve been trying to put together a catch mechanism that can sit behind the spring, like the rainbow, so that I can make a pumpsnap where the pump doesn’t have to stick out in front of the gun. I had some ideas about using a 1/2″ flat endcap as a catch plate, but a post from PVC Arsenal 17 got me thinking about using a simple clothespin trigger on the plunger rod itself, and just using narrower pipe behind the spring to eliminate the space in between, to prevent the pin from being able to wiggle free. What I came up with is surprisingly simple.

First, you cut a 1/2″ cpvc coupler in half, or cut a similarly sized chunk out of whatever 1/2″ fitting you have lying around. Then sand out the inside with a file or dremel until a piece of cpvc slides easily through. Then sand the outside until it fits into the same 1″-1/2″ reducer brushing that you use in the fore of the gun for your barrel. You may need to use a hammer for this step. Finally, add a little tape around the edge to center the fitting in 1-1/4″ pvc. You should now have a piece that looks like this:

The next step is to drill a hole through the gun for the catch pin. Estimate the length of the compressed spring, or put the spring in and hold the gun in it’s cocked position. Now drill a hole from outside the pressure tube, through the reducer and coupler into one side of the plunger rod. Remove the plunger rod and widen the hole into a slot using a cutoff wheel or a hand file. Your plunger rod should look like this:

Note that you don’t actually need the epoxy putty ramp, or the second metal washer on your plunger head for this catch, that’s just the plunger I had lying around at the time.

Now just make a standard clothespin trigger, but with a longer catch pin. You may also want to lightly sand the tip of the catch pin with a file or dremel until it is smooth, so it won’t gouge out big ruts in your plunger rod. Note that I used ceiling hanging wire, since I didn’t have an appropriately sized nail handy. Ceiling hanging wire is sold for less than $10 in huge coils, and it’s used in the construction of drop ceilings. When you get your trigger assembled, it should look something like this without a plunger rod in it:

Note that the trigger here is backwards, for the same reason Carbon’s mk2 trigger was backwards: this design needs a longer pressure tube to accommodate the handle.

So basically, this trigger serves a similar function to Carbon’s mk2 trigger: it gets the trigger and handle behind the spring without adding anything to the outside of the gun. The primary difference is that this design should be easy to set up in a pumpsnap type configuration, where you don’t have easy access to the inside of the plunger because the catch is in the middle of the gun. The added bonus to this style of catch is that you can use any spring that fits in the plunger tube without fear of it fouling up the catch pin.

And, since I’m just so damn proud of my new handle, here’s a photo of the the whole thing put together, but……backwards:

Obviously the gun won’t be configured this way in the future, but I just love that handle. Because of the way I had to reverse the handle to test this design, I’m calling this The Suicide Trigger (although really it’s obviously just a clothespin in a slightly different configuration. )

Update:
Pictured below is the ProtoSLAP, a proof of concept that uses my Suicide Trigger. The blaster is so long because the trigger is completely behind the spring. On a pump-action blaster this will allow the handle to be closer to the stock, providing enough room in the front of the gun for a pump handle to travel back and forth without sticking out past the end.

This blaster is equipped with a Chopper and the handle is wrapped in bright orange moku hitching for an improved grip.

The blaster is otherwise based on Carbon and Rork’s work with the SNAP and is thus pretty comparable with other snaps.

Click for big.

Tags: Clothespin Trigger, homemade, PumpSNAP, SLAP, SNAP, Suicide Trigger, Trigger

This entry was posted on Monday, November 8th, 2010 at 8:54 PM and is filed under R&D. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.