Converting an old Powerline 990

Building or modifying BB, Airsoft, and pellet types of guns. Target practice only!
KaneBlendend
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Greetings all. I've been lurking here for a while, but have yet to find anything similar to what I'm trying to do. Basically I'm looking for ideas on the best way to mount an adaptor to an existing Daisy Powerline 990 hammer valve body. The gun originally could be hand pumped, or fed from a 12g CO2 powerlet. The feed selector mechanism leaks pretty bad now, but the valve and all other mechanisms work just fine.

Previously it used a simple post with an o-ring to mate to this port, but I'd like something more permanent. I'm planning on running a 9 oz CO2 paintball tank into it, as the chamber is already rated at CO2 pressure. Once I get some kind of standard interface on there, I can adapter my way up to an ASA standard.

Once this is all done, I plan on making some kind of bullpup stock and laying the tank up under the barrel. I know it won't be the best, but it's a project I've had in mind for a few years and it's already got the barrel and main firing components in place and working. I don't think the barrel is rifled, but it definitely has some sort of twist going on, so it's not just a smooth pipe.

I'm not quite sure what kind of metal it is, but i don't think there's quite enough to thread for a screw in adaptor. I considered epoxy, but I'm not sure if it'll hold the full 850 psi on such a tiny piece... Maybe if I epoxy a huge lump up and around the screw lugs? Any ideas would be appreciated very much.
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bottom view.jpg
hammer slide is to the left, actual valve is just to the right above the fill port
hammer slide is to the left, actual valve is just to the right above the fill port
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jackssmirkingrevenge
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The first think that comes to mind is to use the standard powerlet fitting, but tap a line into the used CO<sub>2</sub> cartridge. Something like this:

Image

Another option would be something like this:

Image

Image
hectmarr wrote:You have to make many weapons, because this field is long and short life
KaneBlendend
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Hmm, that might be one possible solution. It uses an o-ringed interface block that is held in place, like the powerlet, by the original housing that I was planning on cutting away, or just fabbing a new clamping plate to replace. I'm not sure if the majority of the leak is coming from the interface block joining to the valve body, or the slide valve within the interface block...

If I use the powerlet tapped as an adapter, would epoxy be suitable to replace the o-rings as long as I don't move it? The rifle is coming up on 20 years old, so all of the seals are kinda crap. The o-rings I replaced the originals with don't seem to seal the same. The originals were some kind of squared edged synthetic stuff that crumbled as soon as I touched it.
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co2 assembly.jpg
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jackssmirkingrevenge
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KaneBlendend wrote:If I use the powerlet tapped as an adapter, would epoxy be suitable to replace the o-rings as long as I don't move it?
Assuming you use good stuff properly mixed on a well prepared surface, it should hold.

This project was held together entirely with Araldite and was good for 800 psi with no issues.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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