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Shell Extractor Thoughts/Ideas?

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Shell Extractor Thoughts/Ideas?

Unread postAuthor: Eddbot » Mon Dec 22, 2008 10:03 pm

Hey, I've been contemplating how to remove shells from a breach without just pulling it out, and well, I've hit a wall...

I did alot of research into how spent shells are ejected in real guns (bolt action, not that fancy automatic crap) and i'm pretty sure i've got it figured out. But, it works by grabbing a lip at the base of the casing, and i don't know how to uniformly create a lip in 1/2" copper shells.

lip V
Image

So if you have any ideas about creating a lip, or a different way to extract spent casings, I would appreciate any help/guidance.
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Unread postAuthor: skyjive » Mon Dec 22, 2008 10:14 pm

http://www.spudfiles.com/forums/semi-co ... t8892.html
http://www.spudfiles.com/forums/finishe ... 13838.html

This design is quite simple and elegantly solves the problem of shell ejection, but it is unlike firearm ejection and is a bit finicky to make it work.[/url]
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Unread postAuthor: judgment_arms » Mon Dec 22, 2008 10:27 pm

Putting a lip on copper?

Get your self a pipe swage and swage the end to upset it a bit.
Then heat up the swaged end of the pipe and flatten a draw the rim as need be.

Or you could silver solder on a lip...

What if you had a pin soldered on to the side, and a guide then that aligned the pin, and the extractor grabbed said pin?

Or the extractor could grab on the front of the cartridge...


If it were me, I'd solder on a rim made of a flat piece of copper with a hole in it to let the air through soldered onto the back of the cartridge.
Make a jig to hold it all and run a bead of silver on the inside lip, it should hold well.


These ideas brought to you by a can of Dew... :D



Now my turn for a quick question:
What are you using for a chamber (chamber as in where the cartridges goes)?
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Unread postAuthor: raptorforce » Mon Dec 22, 2008 10:45 pm

yea but there is a reason bullets have a bottle neck because it gets stopped by the barrel so you would also have to make a stopper for the projectile and an ejector is pretty hard to make

btw bolt action and semi and full auto all use the same way to eject bullets
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Unread postAuthor: Eddbot » Tue Dec 23, 2008 1:35 am

skyjive wrote:http://www.spudfiles.com/forums/semi-completed-semi-auto-shell-gun-t8892.html
http://www.spudfiles.com/forums/finishe ... 13838.html

This design is quite simple and elegantly solves the problem of shell ejection, but it is unlike firearm ejection and is a bit finicky to make it work.[/url]


Yeah, seen both of those before, i had the second one bookmarked, then lost it...

judgment_arms wrote:Now my turn for a quick question:
What are you using for a chamber (chamber as in where the cartridges goes)?


I'm a little stumped by that too, i was thinking of clip fed, I'm probly gonna end up using keep_it_real's bolt design with a few modifications. But one of my biggest problems with the project in general, is that i can't find pipe/tube/whatever that is a nice fit around 1/2" copper, it's gotta have a close to 5/8" ID, and for some strange reason, I can't find anything like that anywhere...
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Unread postAuthor: hi » Tue Dec 23, 2008 2:00 am

its a simple lever. the extractor hooks onto the end of the case when the round it chambered. when the bolt is pulled back there is a small pin that pushes the very end of the cartridge, opposite the side of the extractor.

i have thought about making one.

my idea was to have a piece of pvc and drill a hole in the end of it and glue in a small rod. i would cut a groove into the chamber of the gun to accept the pin. the pin is what the extractor would clip onto.

its very simple. i never built it because it would have to be single shot, as the cartridge would only go in one way.

as for a chamber. you could mold a chamber out of epoxy and build it inside of a larger pipe.

my idea is incredibly unrefined and would need a lot of work, but it may be worth it. i wish you luck.
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Unread postAuthor: ALIHISGREAT » Tue Dec 23, 2008 3:38 am

Would the rim need to be dug into the copper or could it be added to the copper's diameter...

because you could do any number of things to get regular lips, for example stick an endfeed coupler on there.
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Unread postAuthor: Ragnarok » Tue Dec 23, 2008 12:12 pm

Take a look at this, because it's not a bad way of doing it:
http://www.boltsniper.com/BS-8/BS8.htm

Alternately, this idea of mine works by pushing the shell out rather than pulling it out:
Image

It's not immediately apparent, but that one pushed the shell out (you can see the parts that do this under the right of the {other} parts that become transparent, although the spring that pushes these parts is absent), the "bolt" could only push and rotate for feeding (It had in this case a double twist to help prevent jamming).

Unfortunately, the spring mechanism that actually ejected the shell from the port after it had been pushed from the breech is missing from this animation.
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Does that thing kinda look like a big cat to you?
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Unread postAuthor: roboman » Tue Dec 23, 2008 12:16 pm

While you're there, check out the FAR, too. It uses a more "conventional" ejector system.
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Unread postAuthor: VH_man » Tue Dec 23, 2008 1:04 pm

Ah, Rag, Thats the ejector sysem im making ATM, Except Simplified a TON.

Just make it so that when you push the shell twoards the barrel, It runs over a little spring loaded lip, And when the shell gets pushed back towards the shell "intake", it is kicked downwards by the force of the barrel acting on it.

So far, I'm actually finding it works more than satisfactorily..... Now to make the darn thing shoot.... :-Dd
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Unread postAuthor: SEAKING9006 » Tue Dec 23, 2008 3:53 pm

Easy-Lip:
Put a coupler on it and cut it way down. Works best with a jig.
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Unread postAuthor: JDP12 » Tue Dec 23, 2008 8:17 pm

aahh.. cartridges! Funny this topic should come up.... I'm working on a fully automatic, magazine fed gun that uses a shell extraction system based almost purely on the "real thing." This is my christmas break project. I'm about to start a worklog thread about it... unfortunately i'm not going to post any plans, because I'm keeping it very hush hush, because I think its a unique way of doing it, and i'm thinking of possibly selling guns based on this, but i will post progress.
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Unread postAuthor: dungdue0 » Tue Dec 23, 2008 9:59 pm

here was my bolt ejection modeled after the FAR

Image

Image

Image


hers boltsnipers FAR bolt and a ar15 bolt

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Unread postAuthor: VH_man » Tue Dec 23, 2008 10:01 pm

very nice.

Now to make it strip the shells off a magazine :-D
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Unread postAuthor: JDP12 » Tue Dec 23, 2008 10:16 pm

lol exactly...
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