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| goose_man |
Posted: 10/22/2007 0:41 AM Post subject: Helical Magazine |
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 Sergeant First Class

Joined: 08 Apr 2007 Posts: 138 390.17 Spud Bux
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I was just doing some work on building my fully auto 3/8" ball bearing pneumatic with a blow-forward bolt system, but I want it to load rounds fast (ie. not gravity fed), and I was thinking of maybe making a helical magazine for it to hold the balls.
Does anyone have any ideas, and possible advice before I venture out on this mission?
-goose_man |
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| Novacastrian |
Posted: 10/22/2007 0:44 AM Post subject: |
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Bloody Aussie

Joined: 11 Aug 2007 Posts: 1622 116.11 Spud Bux
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| Pull apart one of those cheap plastic cap guns and use the ratchet design they use. That or you could make it like an air-rifle 10 shot. |
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| goose_man |
Posted: 10/22/2007 0:49 AM Post subject: |
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 Sergeant First Class

Joined: 08 Apr 2007 Posts: 138 390.17 Spud Bux
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Posted: 10/22/2007 1:02 AM Post subject: |
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Bloody Aussie

Joined: 11 Aug 2007 Posts: 1622 116.11 Spud Bux
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Oh i see, rather i don't- have a clue how to help sorry old chap  |
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| goose_man |
Posted: 10/22/2007 4:42 AM Post subject: |
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 Sergeant First Class

Joined: 08 Apr 2007 Posts: 138 390.17 Spud Bux
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Okay, no problem. Can anyone else help; these maazines have a remarkable capacity for their size, and I'd love to incorporate one into my gun.
-goose_man |
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| jackssmirkingrevenge |
Posted: 10/22/2007 5:37 AM Post subject: |
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 space monkey

Joined: 15 Mar 2007 Posts: 7050 11306.91 Spud Bux
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| copper tube and curve it into a spiral? |
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| goose_man |
Posted: 10/22/2007 9:12 AM Post subject: |
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 Sergeant First Class

Joined: 08 Apr 2007 Posts: 138 390.17 Spud Bux
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| jackssmirkingrevenge wrote: | | copper tube and curve it into a spiral? |
That wouldn't really be a helical magzine. In a helical magazine, there is the inner part which is basically 8 (or so) semicircular grooves going down the outside of the length of a rod. This forms a spoke-like shape if you look down it. This rod is on an axel lengthwise and a torsion spring (that's pre-cocked) will turn it.
The outer part is a tube that has thin rigid exdentations in a helical shape. The inner part is placed in the outer part so that the spokes from the rod (where the grooves are) barely don't touch the exdentations. Picture the ammo in this device, and as the inner rod turns the ammo will be forced up the helical exdentations until they reach the loading mechanism.
I hope that made sense. If not, read the patent I linked to and check out the paintball link.
-goose_man |
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| jackssmirkingrevenge |
Posted: 10/22/2007 9:49 AM Post subject: |
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 space monkey

Joined: 15 Mar 2007 Posts: 7050 11306.91 Spud Bux
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| ShowNoMercy |
Posted: 10/22/2007 10:08 AM Post subject: |
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 Brigadier General

Joined: 19 Mar 2007 Posts: 1119 40.29 Spud Bux
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| Why not use a spiraled copper tube and have a pulse of air hit the end of it before the bolt opens after each shot? |
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| williamfeldmann |
Posted: 10/22/2007 11:10 AM Post subject: |
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 2nd Lieutenant

Joined: 09 Sep 2007 Posts: 216 677.61 Spud Bux
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Does the grooved rod turn or does the auger looking thing turn? I would think the rod.
If your skill at machining is good, I would say try to copy the pics. The rod shouldn't be overly difficult to make and you probably don't have to make it doublestacked for simplicity. Are you going to use something similar to the paintball mags you posted, with a hose of sorts between the mag and the action, or are you going to have the mag feed directly into the action? |
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| goose_man |
Posted: 10/22/2007 14:20 PM Post subject: |
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 Sergeant First Class

Joined: 08 Apr 2007 Posts: 138 390.17 Spud Bux
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I'm going to have a bit of hose to connect it. Since the hose doesn't need to hold pressure, it can be just slipped on and I can fire away. Also, does anyone have a good idea for the torsion spring?
-goose_man |
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| ammosmoke |
Posted: 10/22/2007 18:09 PM Post subject: |
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 Brigadier General

Joined: 27 Sep 2006 Posts: 965 1736.46 Spud Bux
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I don't understand why you don't just use a coil of copper tube, or even lubricated nylon tube and a long spring or series of springs. If you can find a way to lock the end shut with a tiny ballvalve or something you could just use a speedloader and fill it up. Don't make it more complicated than you have to...
EDIT:
Make that a coil of tubing inside a pipe. |
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| origin unknown |
Posted: 10/22/2007 20:10 PM Post subject: |
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 Colonel

Joined: 14 Apr 2007 Posts: 532 894.45 Spud Bux
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| You could get a torsion spring from one of those Hi-cap airsoft mags. Just buy a few cheap mags on ebay and remove the springs. |
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| goose_man |
Posted: 10/22/2007 21:36 PM Post subject: |
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 Sergeant First Class

Joined: 08 Apr 2007 Posts: 138 390.17 Spud Bux
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| ammosmoke wrote: | I don't understand why you don't just use a coil of copper tube, or even lubricated nylon tube and a long spring or series of springs. If you can find a way to lock the end shut with a tiny ballvalve or something you could just use a speedloader and fill it up. Don't make it more complicated than you have to...
EDIT:
Make that a coil of tubing inside a pipe. |
The helical magazine holds a lot of ammo and the spring could be a lot smaller than with your idea. Also, with that idea, the balls would put more pressure on the bolt when it's closed. The helical magazine only has to spin a few times (with a torsion spring that's real easy) whereas with a long spring forcing the ammo through a tube, the spring has to compress to many times smaller than its rest position.
-goose_man |
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| ammosmoke |
Posted: 10/22/2007 22:39 PM Post subject: |
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 Brigadier General

Joined: 27 Sep 2006 Posts: 965 1736.46 Spud Bux
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Soo,, It moves like an auger? And the bb's stop it until they are fed into the gun... ahhh I get it now. Well, still, my design would hold a lot. Probably about the same per volume of pipe. Idk, in my mind my sounded better, but that is prob because I am biased about my own ideas lol.
Would this help?
http://www.tapplastics.com/shop/product.php?pid=154& |
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