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| jackssmirkingrevenge |
 Posted: 08/19/2010 13:00 PM Post subject: |
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aspiring machinist
Joined: 15 Mar 2007
Posts: 18060
32518.54 Spud Bux
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| JDP12 |
| Posted: 08/19/2010 15:05 PM Post subject: |
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Major General
Joined: 30 Mar 2007
Posts: 1872
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Awesome!!! JSR that super cool. Did they seem to be pretty consistent as to releasing the BB-- not too much variance in the silicone?
That's super cool good job
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| dewey-1 |
| Posted: 08/19/2010 15:06 PM Post subject: |
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Brigadier General
Joined: 28 Mar 2007
Posts: 957
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JSR;
Great to see that you are making some progress on your cartridge endeavor!
Looks impressive as is. Can only get better! 
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| Ragnarok |
| Posted: 08/19/2010 16:05 PM Post subject: |
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Lord of Karma
Joined: 19 Dec 2006
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16113.53 Spud Bux
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| jackssmirkingrevenge wrote: | | Well, finally, SUCCESS!!!! |
Pah. I'm disappointed. This should clearly read "Huge Success". 
But good work anyway.
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| jackssmirkingrevenge |
| Posted: 08/19/2010 21:43 PM Post subject: |
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aspiring machinist
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Cheers guys, though it will be a "huge" success when I can have it fire and cycle a semi-auto action ;P
| Quote: | | Did they seem to be pretty consistent as to releasing the BB-- not too much variance in the silicone? |
If I pressurise the cartridge until it pops, it holds the BB until about 150 psi very consistently. The important thing is to always push the BB to the same depth into the seal.
Here's a couple of pics of the "magnum" version for a 3/8" bearing, I'll test it some time this evening when it's fully cured. The one thing I'm not sure of is the seal pop-off pressure. Note how the schrader is recessed in the cartridge body in order to afford some measure of protection if it hits the ground tail first.
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| Ragnarok |
| Posted: 08/20/2010 3:32 AM Post subject: |
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Lord of Karma
Joined: 19 Dec 2006
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| jackssmirkingrevenge wrote: | | Cheers guys, though it will be a "huge" success when I can have it fire and cycle a semi-auto action |
No, that will be a triumph. 
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| CpTn_lAw |
| Posted: 08/20/2010 4:10 AM Post subject: |
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Your friendly scientist
Joined: 11 Sep 2005
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| Super happy you finally had a nice motivator boom !! This will most definately be a major step-up in the spudgun achievment list!
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| POLAND_SPUD |
| Posted: 08/20/2010 4:53 AM Post subject: |
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Lieutenant General
Joined: 13 Oct 2007
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| Ragnarok wrote: | | jackssmirkingrevenge wrote: | | Cheers guys, though it will be a "huge" success when I can have it fire and cycle a semi-auto action |
No, that will be a triumph. |
nope... that will be an EPIC WIN!!
@jsr
I am quite sure you get acheive this goal. You know what I think about cartridges right ??  somethign tells me that larda will soon show you that you don't need cartridges to build a semiauto hybrid
yeah, I know I know... you want ejecting cartridges
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| jackssmirkingrevenge |
| Posted: 08/20/2010 13:32 PM Post subject: |
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aspiring machinist
Joined: 15 Mar 2007
Posts: 18060
32518.54 Spud Bux
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| CpTn_lAw wrote: | | Super happy you finally had a nice motivator boom !! |
You can take some credit as well for your own hybrid and ignition tips, without which I would not have revisited this project
| Quote: | | yeah, I know I know... you want ejecting cartridges |
At least you understand 
Well, I tried it out, the seal will retain pressure without popping out up to 45 psi, so I'm limited to a 4x mix - which worked (BLAM! even without a barrel the BB left a 3mm deep dent in my wooden wardrobe )
I'm going to reglue it with araldite and see if I can increase the pop-off value.
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| CpTn_lAw |
| Posted: 08/21/2010 13:35 PM Post subject: |
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Your friendly scientist
Joined: 11 Sep 2005
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| jackssmirkingrevenge wrote: | | CpTn_lAw wrote: | | Super happy you finally had a nice motivator boom !! |
You can take some credit as well for your own hybrid and ignition tips, without which I would not have revisited this project
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I will most certainly follow your steps when i come back (currently at my dad's) and try to see what's doable with a standard piezo and some polyethylene tubing!
The credit here is all yours, and my hybrid is far from competing with most of 'em showed here!
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| spudamine |
| Posted: 08/22/2010 0:30 AM Post subject: |
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Master Sergeant
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I'm really interested to see how well scaling it up goes and how high a pressure the seal will hold to, the small one looked brilliant.
Do you have any feeling for whether the gases will seperate in the cartridge over time, I know this was brought up before but nobody managed to make a working one to test it, personally I recckon it won't be a problem.
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| jackssmirkingrevenge |
| Posted: 08/22/2010 3:23 AM Post subject: |
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aspiring machinist
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Posts: 18060
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| CpTn_lAw wrote: | | The credit here is all yours, and my hybrid is far from competing with most of 'em showed here! |
Of course there are more advanced hybrids on the forum, but it was this shot that really hammered it home that there is something in this hybrid malarkey for me
| Quote: | | Do you have any feeling for whether the gases will seperate in the cartridge over time, I know this was brought up before but nobody managed to make a working one to test it, personally I reckon it won't be a problem. |
We had discussed it here, if anything the mix should be even more homogenous the longer it's left.
I'm a bit stumped with finding a good seal for the cartridge, in the meantime I'm making a "traditional" hybrid with a burst disk - still a mini, but I always wanted to make a powerful 0.22" pistol, the problem with a pneumatic is that it would be too loud even with an oversized suppressor, but I figure it's easier to muffle the noise of a hybrid because you can kill pressure not just by expansion but by cooling the propellant gasses
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| CpTn_lAw |
| Posted: 08/22/2010 4:52 AM Post subject: |
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Your friendly scientist
Joined: 11 Sep 2005
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Hehehe it is planned too to make a small caliber hybrid pistol!
I'll try to be as inventive as you
Suppressing a hybrid works much better than upressing a pneumatic, however unsupressed, the hybrid wil be much much more loud thn the pneumatic !
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| jackssmirkingrevenge |
| Posted: 08/22/2010 5:07 AM Post subject: |
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aspiring machinist
Joined: 15 Mar 2007
Posts: 18060
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Looking forward to seeing your results I'll do some performance evaluation first - spark gap is *really* tiny, I can just put a sheet of paper between the electrodes, so I'm hoping to take it to at least 8x. For the suppressor I have some nice heat-absorbing copper tube in mind, with plenty or steel wool packed in, should do the trick. The plan is to end up with something like the Welrod.
As to the cartridge, I decided screw the large calibre and let's go with 0.177" - it looks pretty silly now, something along the lines of the 7.92x94 anti tank cartridge fired by the Panzerbüchse 39, but it should give plenty of velocity. Once I get to the point of getting reliable function, I'll make a barrel and breech for it then hopefully move to a direct blowback action.
Last edited by jackssmirkingrevenge on 09/16/2010 6:17 AM; edited 1 time in total |
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| JDP12 |
| Posted: 08/22/2010 6:24 AM Post subject: |
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Major General
Joined: 30 Mar 2007
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| Looks awesome, I'm a fan of the Welrod myself.
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