rimless cartridge extraction without moon clips


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General Geoff
August 6, 2008, 01:16 PM
I was looking at the extractor on my Smith 610, and had an idea. What if you cammed the extractor action, so the surface extractor assembly comes out just enough to clear the cylinder, then twists to catch all the cartridges under the rebated rims, then continues to push all the cartridges out similar to rimmed brass?

I always though this would be a really neat idea.

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Technosavant
August 6, 2008, 01:32 PM
Seems like it would work. The catch would be if the extractor would be able to catch that rim 100% of the time (thin it out so it will fit) but still be thick enough to function properly.

Given that moons aren't too difficult to load and unload and make the reloading process FAR faster, I'm not sure that folks would want to pay the extra that the design & construction of such a device would add to a revolver price.

More power to you if you want to try developing it though. It might even be able to be retrofitted to existing revolvers, depending on how you did the camming.

Sistema1927
August 6, 2008, 01:37 PM
I would think that it would add an additional level of complexity, thus increasing the chance of failure.

What's wrong with moon clips?

General Geoff
August 6, 2008, 01:42 PM
Well the thing is, so long as the extractor stays flush with the cylinder face during normal operation, it would be 100% moon clip compatible anyway (it would just push the cartridges out along with the moon clip instead of engaging the rims during the first few mm of travel). The extractor would have to be designed so that it looks sorta like an octopus though, with a circle of hooks, to more positively grab the rims. I'd say they should be about 1/3 of a circle, any more than that and the spent casings would be a bit of a pain to jiggle free from the extractor. :)

TallPine
August 6, 2008, 01:47 PM
What's wrong with moon clips?


What's wrong with rimmed cartridges? :D

Virginian
August 6, 2008, 01:49 PM
I don't think you can do it because the cam angle to turn that far, that fast, would be too severe to have it function purely as a cam, unless you went to an extreme oversized ejector, depth wise. Given enough resources, anything is possible, except government efficiency. Perhaps have the cam guide cut, but the user would have to turn and push to get things started.

General Geoff
August 6, 2008, 01:49 PM
I would think that it would add an additional level of complexity, thus increasing the chance of failure.

A cammed extraction mechanism, I would argue, doesn't really increase the chances of failure. And it's not a critical functioning part of the firearm, i.e. the gun will still cycle and fire properly even if it does bind, jam, or whatever. It's also not under any kind of load except for a weak spring retention, so there's not a whole lot that would cause it to bind or otherwise not work.

General Geoff
August 6, 2008, 01:55 PM
I think there'd be enough angle for it to work. Figure about 2mm of lengthwise travel and 3mm of twist. The edges of the extractor rings would have to be cut on an angle parallel to the cam angle so that it unseats from the cylinder face at that same angle and slips into the rim groove of the cartridges.

Shear_stress
August 6, 2008, 01:55 PM
Take a look at the S&W 547. It used spring-loaded fingers to extract 9mm cartridges without the use of moonclips. An elegant solution that never really took off.

General Geoff
August 6, 2008, 01:59 PM
^^About the 547. That's an awesome extractor system. I want one now. :)

Jim Watson
August 6, 2008, 02:21 PM
This MAY be how the rimless extractor on one of the Expensive European Revolvers works, Manhurin or Korth; but I could not find any details to say for sure.

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