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Snap-compact

The true plunger rod-less SNAP

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#1 Boot

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Posted 09 October 2010 - 07:36 AM

As usual, feel free to skip the long and probably boring story that starts all of my writeups.

After the fiasco that was my attempt at the RTP I realized that the concept was more important than the initial product (since after a concept was proven a better model could be made). I wanted to attempt a standard Snap, but I don't find copying a preexisting design nearly as interesting as either formulating a new one, or improving on a old one.

I looked at the many innovations in the snap series dealing with ROF, Plunger mass and size and began formulating an idea in my head.

Note: This was made before the influx of pump action homemade's, but as stated in the modification and paint job's thread I have not had enough time to fully document all (or any, actually) of my projects so I'm doing this now :) . This is my take on a pump action SNAP, and although not as pretty, I find that it functions almost as well.

The original inspiration for this came from the Acebow (made by Ace on Nrev) and carbon's Snap and revolutionary clothespin trigger so... PROPS!

Read on from here, or just look at the pretty(ish) pictures.

The idea of this blaster is to combine the priming and breech loading motion into one allowing for higher ROF and the possibility of using a clip of some sort (Although, like on the Mirage I have not had the resources, or, since I'm back at school, patience to make a clip). Although I haven't made a clip for it I have tested with a stack of darts held in position by a couple toothpicks and hot glue and the feeding motion seems perfectly smooth.

So, without further ado (because we all know there has been enough, erm... ado already) here is the Snap-Compact.

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Ugly, yes. Almost as bad as my nano stephans; but it is the concept that goes into this that I think is revolutionary.

First things first the thing is tiny. Because the barrel replaces the priming handle (explained later) the whole thing is the size of a Primed snap without a barrel.

How it works is simple, yet in my opinion quite effective.

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You pull the breech open and the dart drops, or is loaded in.

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While pushing the breech closed, the end of the barrel contacts the front of the plunger (the two pvc endcaps). First, the dart is fully pushed into the barrel, and when the end of the barrel contacts the plunger head the breech stroke continues, compressing the spring and locking the plunger head in place (below)

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Then, simply pull the barrel assembly back to the starting position. The dart is in the barrel, the plunger is back and the spring compressed; you're ready to fire.

Although I know this all sounds ridiculously complicated the firing motion is quite simple. Pull forwards slightly, push all the way back, and pull back to starting position. Exactly like a standard pump action setup, just with the slight pull at the beginning.

The reason this all works without a rod to stabilize the spring is because the [k25] used fits snugly into the PVC used. Again, because I'm doing this in China the materials are different but the PVC seems to be standard 1 1/4" Snap material.

Because of this the plunger just has to be the sealing surface in this case (I'm sorry) E-tape (Again, China. As far as I can tell no McMaster here), and the catch surface; the second endcap.

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This gets rid of the plunger rod entirely, no wire, no PVC, no fuss.

The only difficulty in doing this is that the clothes pin trigger nail (wow that sounds long winded) must be rounded very well so that it won't catch on the spring while priming. Because the spring fits snugly, but loosely this helps nudge the spring upwards rather than catching. I also added a bit of Vaseline just because it can't hurt, and hopefully this way it won't scratch the spring up as badly.

The rest of it is simply for the sake of functionality. A trigger relocation, or a wooden dowel taped to the trigger allows the back of the blaster to be used as a stock further minimising the blasters size, a T and the front with a hole drilled for the barrel exit acts as a handhold to prime the blaster, and the flexible string (taken from my BBB) keeps you from pulling the entire thing apart.

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And because I know how absolutely confusing this must be here is a:

Firing video!

I get the feeling this writeup is much more confusing than my Mirage one and for that I apologize. Feel free to ask any questions, and make any comments because more of these are to come, and hopefully they will get better and better (as mentioned in the Mods and PJ's thread I have a backlog of projects, and I will be releasing them from least to most interesting/ revolutionary. This is the least (after my very mundane draw extended NF)

In terms of manufacture the ONLY differences between this and a standard snap are the plunger, the barrel assembly, and maybe the care taken in creating the catch.

Although I realize this is terribly ugly, the ranges speak for themselves. This is getting 90-100ft ranges, and that is with: 3/4 of a [k25] for power, and an E-tape seal (on both the plunger AND the gap between the moving and stationary parts of the breech)

I think people were right about how much plunger mass effects these things, for what it is this thing is ridiculously powerful.

Here's to hoping someone makes a cleaner one of these,

-Boot
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QUOTE
If you try to shoot over 45 feet with a magstrike accurately you fail

I beg to differ

#2 Carbon

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Posted 09 October 2010 - 09:03 AM

It took me a couple reads, but I think I get what you're doing here. This seems to work in a similar fashion to the SNAP-5, as the barrel is what slides back and forth for the priming action. However, you managed to build in a breech, and get rid of the plunger rod entirely...nice work making use of the [k25] size.

Any reason you left off the rubber washer plunger seal? I can't see a reason why it wouldn't work....aside from the vaseline you used for spring lube.

Nice job! I always like seeing a different approach to a blaster, and this is definitely it.
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#3 SgNerf

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Posted 09 October 2010 - 09:20 AM

Boot,

Cool! Now thats a really simple yet functional design you've got there, reminds me of a Longshot plunger system where the bolt pushes back the plunger until it catches, then the user pushes the bolt forward to close the breech and complete the priming process. Its an ideal base design for clip compatible breeches.

I also like the fact that it uses a free-floating "beanz-style" plunger head that does away with the need for a plunger rod, allowing more flexibility in blaster design.

No exposed plunger rod = No more clipped fingers!

Thanks for posting it up! :)

Edited by SgNerf, 09 October 2010 - 12:52 PM.

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#4 Boot

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Posted 09 October 2010 - 06:48 PM

Thanks for the feedback, glad to see the wrtiteup wasn't so confusing as not to get the idea across.

Any reason you left off the rubber washer plunger seal?


The washer seal would work great, and I do have silicon lube (the vaseline is only on the firing pin because it is of a thicker consistency and so stays on better), but try as I might I have been completely unsuccessful in finding large enough rubber washers, or even rubber sheeting to cut my own washers. Thats why I called this more of a concept (even though I know how much people hate that word here :P )

Also, Wow! I never noticed that about the snap-5, I always thought it was basically a Snap with a homemade turret on it, I guess that's what I get for only skimming through the directories.

Thanks a lot for the feedback though, it means a lot (especially since a "different approach" was exactly what I was aiming for :) )

reminds me of a Longshot plunger system where the bolt pushes back the plunger until it catches, then the user pushes the bolt forward to close the breech and complete the priming process. Its an ideal base design for clip compatible breeches.


Yes, I believe the longshot system was the inspiration for the Acebow, which functioned like a singled longshot (which was part of the inspiration for this build).

It's funny though, I didn't even think of the "face diddle" component that occurs with some snaps, but looking at it, when in use the plunger head is literally a few centimeters away from my face (when primed), I guess a kindof unintentional merit of this design is that all the moving parts are kept inside the plunger tube.

Thanks a lot for the feedback, again, it means a lot.


To everyone: there is more to come, the next of my snap designs is on its way :o

(its also a bit nicer to look at)

Edited by Boot, 09 October 2010 - 06:49 PM.

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QUOTE
If you try to shoot over 45 feet with a magstrike accurately you fail

I beg to differ

#5 Carbon

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Posted 10 October 2010 - 12:51 AM

Thats why I called this more of a concept (even though I know how much people hate that word here :P )

Concepts that have actually been tried out and built are welcomed with open arms. It's the concepts that exist only as half-baked diagrams in Paint that are looked down upon.
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