Bullshark 750 fps marble launcher

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Anatine Duo
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Fri Mar 10, 2017 4:02 pm

The Bullshark!
bullshark right side.jpg
Finally done! Salvaged materials not only from garbage and whatnot, but also from my second ever airgun in 2003!

Other than the trigger and pilot it's a fairly standard co-axial muzzleloader. I've had it up to 240 psi with no leaks but more likely I will be plinking with it at 150psi.

Weight: under 5lbs with scope

Materials: ABS reinforced with Kevlar main tube, aluminum .64 cal barrel, pine and plexiglass stock, pultruded fiberglass bar, pvc endplugs (and maybe valve I can't remember), PMFG saddle-blanket (holds main tube to stock via screws), Kydex clips, poplar ramrod, mineral reinforced PET scope mount, brass pins, phenolic trigger, aluminum trigger guard

Power:

marbles @150 psi 630fps 79 ftlb
marbles @240 psi 750fps

.625 steel @240psi 500fps 140 ftlb

This launcher lives in Canada so it is stored with a trigger lock and I have the appropriate license.

I am quite proud of the pilot which is easy to fabricate with primitive tools (saw, file, drill) and operates mechanically so it feels like a real trigger. Also quite happy with the reinforced pressure tube... I happened to have Kevlar and aircraft epoxy laying around ;)

The texture coating is made by painting on Titebond 2 and sprinkling on cork powder, then priming and painting.


I preserved the overall shape of the original stock (I recently shot through that old stock:) but from a design perspective I've moved on.

Too cold for video but I'll get some up soon and hopefully some heavier slugs.

Some discussion of the work in progress: http://www.spudfiles.com/pneumatic-cann ... 26574.html
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bullshark left side.jpg
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Sat Mar 11, 2017 12:53 am

Awesome looking launcher! I'm excited to see you're video. I looked through the thread you referred, but didn't see the big reveal on the lift-off valve mechanism. What are the trigger linkages made out of? What has been the most successful sealing material for the mechanical finger? Does the trigger have to be re-latched every time you shoot?
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Anatine Duo
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Sat Mar 18, 2017 10:59 am

Still too cold for my planned video...

Trigger linkage is fiberglass bars intended as tension bars in fences. Any light rigid material would do, and I think I would have tried wood if it weren't too late at night to run the table saw.

Yes the sear is reset every shot... all the air is dumped. Currently my favorite liftoff material is the leather pad smeared with Vaseline or lard, or a piece of balloon inserted between the pad and the brass nipple. It reminded me of replacing the primer on my BP muzzleloader.

Turns out it seized this morning. I suspect the extreme temperature variations and attendant moisture issues are the problem. A shot of Fluidfilm in the fill valve and 3 dry fires seems to have fixed it. That reminded me of putting a drop of PellgunOil in my CO2 guns.

Thanks!
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encohen
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Fri Apr 07, 2017 1:14 am

That's a really good looking gun you got there! muzzle velocity is quite impressive for the pressure . what type of valve and pilot you got?
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Air2theBrain
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Sun Dec 03, 2017 6:38 pm

I've just caught this...the build quality is fantastic well done. :wink:

Aircraft epoxy sounds perfect...hmm. 8)

Impressive fps figures. :)
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