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New Seac Shotgun

popgun pete

Well-Known Member
Jul 30, 2008
3,038
591
153
Australia
Recently looking at the Carbon C4 "Mr Dark" it would be interesting to see if an analogue could be made based on the Seac Sub "Shotgun". If a bulbous air tank could be grafted into the lower rear section of the gun to provide the same belly shape this would make an interesting gun in terms of tracking while mainting a more normal compression ratio, but how to do it? Some time back we saw a gun with an air tank in a rectangular block under the rear of the gun which itself was narrow, but nothing more was heard of it. From memory the name started with an “S”.
seac sub shotgun modified.jpg
 
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popgun pete

Well-Known Member
Jul 30, 2008
3,038
591
153
Australia
The gun I am thinking of was discussed on this forum, from memory the tank connected to the butt of the grip handle and was a rectangular shape externally, but had a bunch of interconnected tubes inside it for the pressure vessel. I remember having misgivings about the tank busting off the gun, but it certainly was different. It had its own website where you could order a gun, as they seemed to be built to order, and had been reviewed in a few places on the Net.
 
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Diving Gecko

shooter & shooter
Jun 24, 2008
1,270
311
138
Shanghai
Was it the one that looked like a "normal" arbalete? With a wooden stock?

Making a buoyancy belly can be done by glueing foam onto the reservoir, shaping it and the covering it in carbon or glass fiber. The Carbozzi guns are made like this. Some of them use the Palengas foam wings as a starting point.


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Diving Gecko

shooter & shooter
Jun 24, 2008
1,270
311
138
Shanghai
Yes, I think it had a timber stock, it was a pneumatic in operation, but had the body of an arbalete and from memory pre-dates the "Airbalete".
Yeah, it seemed to me that it wasn't a production gun but maybe just a tinkerer making a few of them.

As you know, I'm hoping one day to actually make a one piece reservoir like this (slim front with a belly). I think it'll be more voluminous than the standard compression reservoirs. But if anything, that should only be an advantage, right? I mean, the power curve won't taper off near the end of the shot. And I'm thinking, it's normally the force right at the latching point that gets me sweating. Even if it doesn't start much lower, that's probably not the big issue.
But if it has a Mirage system in it, that's a mute point. But if I get this reservoir made, perhaps the first one will be standard loading.


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popgun pete

Well-Known Member
Jul 30, 2008
3,038
591
153
Australia
The larger the tank volume to barrel swept volume then the better as the compression ratio approaches 1.0 as Vb/Vr becomes very small.

CR = initial volume divided by final volume or (Vb + Vr)/Vr = Vb/Vr + 1

I was looking for this odd-ball gun, and I am sure that I have filed it somewhere, as I was thinking of how to attach a “piggy back” tank pack under the Seac Sub gun without weakening the existing 40 mm diameter rear tank. From memory the arbalete style pneumatic gun had a bunch of interconnected tubes side by side in its rectangular shaped tank block and something like that could be curved under the main tank here. A sketch shows three tanks in a curved outer shroud underneath the gun looking back from the muzzle. These sub tanks being cylinders they will hold the pressure, the problem would be to interconnect them without causing throttling at the interconnections.
extended tank.jpg