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[WIP / Design] Chimera

Chimera Caliburn

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#1 stuck by stefan

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Posted 13 March 2018 - 11:42 PM

Here's my latest doodling in Solidworks. I'm trying to create a more compact and portable version of the Caliburn.

The design uses a 1.5" id plunger tube as opposed to a 1 3/8th" that has become the norm. The draw length is only 5 inches, but it has been shown that the traditional 6+ inch draw of a "full [k26]" is pretty inefficient and most of the energy in a full [k26] setup is wasted.

Friction concerns is the main issue with running a 1.5" plunger tube, but I have plans for a floating O-ring seal that should address this issue.

Overall length with the stock collapsed is 28.5" at the moment, 4.5" shorter than the Caliburn. And if my calculations are correct, it should have the same if not better performance than the Caliburn.


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Edited by stuck by stefan, 13 March 2018 - 11:44 PM.

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#2 CaptainSlug

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Posted 14 March 2018 - 07:17 AM

You don't really have to start from a blank sheet if all you want is a shortened Caliburn. You can just trade available plunger stroke for spring compression (and as a result slightly less deadspace). You can also shorten the ramrod a bit to gain a little effective barrel length.

 

Your multi-catch plunger concept however is really interesting. And that's one thing that a diameter increase can accomplish. Given that the Caliburn was designed with the option of using Schedule 40 PVC for the plunger tube you probably have room in the stock area to use 1-1/2" ID 1-5/8" OD tubing for the plunger tube by just redesigning the pieces for the stock.


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#3 stuck by stefan

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Posted 14 March 2018 - 10:41 AM

You don't really have to start from a blank sheet if all you want is a shortened Caliburn. You can just trade available plunger stroke for spring compression (and as a result slightly less deadspace). You can also shorten the ramrod a bit to gain a little effective barrel length.

 

Your multi-catch plunger concept however is really interesting. And that's one thing that a diameter increase can accomplish. Given that the Caliburn was designed with the option of using Schedule 40 PVC for the plunger tube you probably have room in the stock area to use 1-1/2" ID 1-5/8" OD tubing for the plunger tube by just redesigning the pieces for the stock.

To be honest, I just wanted to challenge myself to design a mag-fed springer from scratch. I personally prefer fabricating my own designs as opposed to something that everyone else already uses. But as I got further in the process, it ended up borrowing a lot more design concepts from the caliburn than I intended. I guess that that shows how good the Caliburn's design is.

I'm hyped about the multi-stage catch too. If designed right, it should allow for max compression with multiple spring types.

Edit: Along with this project, I might try to fit the multi catch system into a caliburn. Hell, I think it might even fit into a 1 3/8th" PT.


Edited by stuck by stefan, 14 March 2018 - 10:43 AM.

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#4 jimmythefly

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Posted 30 March 2018 - 04:39 PM

I was just looking at what other seals are available that might reduce friction/increase performance. McMaster doesn't show anything for the 1.375" ID, however there is this teflon version for 1.5".

 

https://www.mcmaster...526n16/=1c76sfl

 

I wonder if it would boost performance at all, or if it relies on a smoother more perfect bore than what we might get from the usual tubing sources. 

 

 

In trying to figure this stuff out, I found this design guide, which is just full of information.  I haven't been all the way through it yet but figured you guys might be interested.

http://www.applerubb...esign-guide.pdf


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