15 replies to this topic

[koree]

A while back I posted to the prototype for a new pump action blaster.
The basic idea was to split up the spring and plunger into two different stacked tubes. This would shorten the blaster a few inches, and it would raise the height of the barrel. (It’s personal preference but I like the barrel to line up with the top of my shoulder. I think it makes aiming easier.)


Due to my crappy craftsmanship the best I could do with the plans I posted was this. It shot alright but the construction was really shoddy. It should also be noted that Hooongfu named the blaster the “Double Rainbow” in reference to a certain youtube video of course.



So I gave the Google SketchUp files to my buddy Andtheherois and he came up with these beauties.




So this weekend I went over and with Andtherherois’ help, we built another one for me. And by help, I mean he did most of the work while I would occasionally screwed something together.



I

Differing from Andtheherois’ versions, this one uses a polyester tube as a stock with a M14 rifle stock pad on the end. This stock ended up being quite lighter than Andtheherois’ fixed stock and more comfy than his folding stock. However, it was also much more difficult to mount, as polycarbonate pieces had to be cut out to fit in between the tubes.



Here it is among its contemporary pump action blasters. We have the rainbowpump rev 2 and a pumpsnap rev 2. Despite its longer draw the double rainbow is about 5” shorter than the rainbowpump and 2 inches shorter than the pumpsnap.

So I don’t really have a write up, but the following should help anyone with the right set of tools, skills, and persistence build the base blaster.





And that’s it. Questions, flames, and comments are all welcome. And thank you Carbon for the CPT, Split for the skirt seal, and Beaver, Stark, and Atomatron for the rainbow catch.

Edited by Aeromech, 23 November 2015 - 04:05 AM.

[Carbon]

What I find most interesting about this design is that it shows that offset forces don't cause nearly the friction/binding problems that I thought they would. I've always worked to make sure that my forces are as linear as possible to minimize friction...and then this design comes along and screws with what I always assumed to be true (sorta like Beaver's offset priming bar/screw). While I'm sure that there are losses due to friction and an inefficient plunger push, the tradeoff looks to be worth it in terms of ergonomic benefit (assuming standard RainBow ranges).

TL;DR This fucking rocks and makes me reassess what is a feasible design. Thanks for messing with my mind.

Edited by Carbon, 11 December 2012 - 09:51 AM.

[LT DAN ICE CREAM]

How sturdy is that plunger rod to spring rod bridge? Is there any sort of safety device that prevents it from crashing violently into the ends of the tubes?

[andtheherois]

I'd like to add that this blaster shoots just as well as any other 7" draw blaster regardless of the extra weight and friction. However to further offset those forces, Koree and I swapped out the [k26] for K27s. With the K27, this blaster still gets 7" of draw and sends slugs fish tailing out of a 14" barrel (porting the barrel 8 times fixed that problem).the templates for these were all done on graph paper so I no longer have them, however it should be easy enough to make them. I do however, have the templates for the rainbow catch for square plungerrods. I'll upload those once I get home from work.

To answer Dan's question. The plunger rod connection is very sturdy. It's another length of 3/8 square rod screwed onto both ends with. 3/4" log screws. We cut the rods slightly longer and made the channels slightly deeper to keep everything from touching that would cause harm.

Edited by andtheherois, 11 December 2012 - 10:53 AM.

[koree]

TL;DR This fucking rocks and makes me reassess what is a feasible design. Thanks for messing with my mind.

Hehe, thanks and always happy to mess with your mind.

How sturdy is that plunger rod to spring rod bridge? Is there any sort of safety device that prevents it from crashing violently into the ends of the tubes?

As Andtheherois said, it's plenty sturdy. We put a K27 in there and it's holding up just fine. Though, I put a [k26] back in mine just to ease priming.

And for things violently crashing into eachother, the rod lengths were chosen so the bolt which is used to prime the blaster is hit. In the unlikely event that something breaks, it would probably be the spring tube first, which can easily be replaced.

Edited by koree, 11 December 2012 - 02:47 PM.

[Phoenix66]

So the catch and everything is on the bottom tube, where just the plunger is on the top tube correct?
Is it absolutely essential that the top to be clear. I know the bottom tube has to be clear for the catch,, but is it absolutely essential for the top tube?
Are the 2 inch a quarter PVC tubes screwed on To each other, or do They just sort of float?
Also, could we have a firing demonstration just to show in more detail how the blaster works?

Edited by Phoenix66, 11 December 2012 - 05:30 PM.

[ChaosPropel]

Is it absolutely essential that the top to be clear. I know the bottom tube has to be clear for the catch,, but is it absolutely essential for the top tube?

It's not essential for either to be clear. Clear tubes are just helpful for putting those circular plates/the handle in.

[andtheherois]

The two tubes are screwed together trough the Catch, using counter sunk screws in the PT and then held together through whatever method you use for the stock. Hell you dont even need to use clear PVC for the catch area, since Louie has templates for a catch area in his revshot templates using opaque PVC. you can just use that to mark where you would put your catch. Our catches are held in via 2 set screws on the bottom and then two screws on the top that go through the PT. Probably not the best way to do it but it makes it look cleaner since there are less screws/no sideplates to worry about. However with only two screws it'll wobble more. It's also improtant to drill them as centered as possible on the tubes or they'll be off center when you put them together.

[koree]

Is it absolutely essential that the top to be clear. I know the bottom tube has to be clear for the catch,, but is it absolutely essential for the top tube?

No, but it looks really pretty on my wall along with the rest of my homemades. (Yes, I was just finding an excuse to post this pic.)

[Mully]

This looks very good.
Just one question:
Where did you get the handle?

EDIT:
Thanks man,
I'll check em out.

Mully

Edited by Mully, 11 December 2012 - 09:41 PM.

[koree]

This looks very good.
Just one question:
Where did you get the handle?

It's a Bob Long trigger frame. You can find them online quite easily. I got mine on eBay.

[Daniel Beaver]

Is there any reason why the top plunger tube has to be longer than the draw length? Seems like you could reduce the overall length (blaster + barrel) by 6" if you did that.

[quertyman]

This is somewhat off topic (not really) but what are those paintball/airsoft/whatever handles that you use for your rainbows?

Also is there any advantage to using this design? Besides the different barrel angle and being like 2" shorter.

Edited by quertyman, 11 December 2012 - 11:34 PM.

[Zorns Lemma]

Could either you or andtheherois post pictures of the blaster primed? I want to see how things line up. (I realize there are some pictures in the homemades thread, but those aren't quite explicit since it is aimed to be gun porn >_>)

I'm in Carbon's boat here, my prior experiences with offset priming is that they caused total dicks-in-mouth experiences when trying to operate the blaster. I'm glad you figured out a way to get it to work well. It probably has to do with how the move to concentric tubes and plates helps center the priming bars and prevent skewness?

Edited by Zorn's Lemma, 11 December 2012 - 11:51 PM.

[koree]

Is there any reason why the top plunger tube has to be longer than the draw length? Seems like you could reduce the overall length (blaster + barrel) by 6" if you did that.

On mine, the top plunger tube is actually shorter than the SketchUp screen cap I posted. And you're right, by shortening the top tube we could probably shorten the blaster, but not quite the 6". The main reason being that the back of the top tube is used to secure it to the bottom tube using screws not unlike how one secures a handle onto the body of a rainbow pump. But yeah, I should try to minimize that next time.

This is somewhat off topic (not really) but what are those paintball/airsoft/whatever handles that you use for your rainbows?

Also is there any advantage to using this design? Besides the different barrel angle and being like 2" shorter.

I've addressed all of these, please reread.

Could either you or andtheherois post pictures of the blaster primed? I want to see how things line up. (I realize there are some pictures in the homemades thread, but those aren't quite explicit since it is aimed to be gun porn >_>)

I'm in Carbon's boat here, my prior experiences with offset priming is that they caused total dicks-in-mouth experiences when trying to operate the blaster. I'm glad you figured out a way to get it to work well. It probably has to do with how the move to concentric tubes and plates helps center the priming bars and prevent skewness?

Thanks! As for the pics, here is one primed. It might be better for andtheherois to post a pic of the folding stock one primed however.

[koree]

Made a latex tubing powered version.



The catch interface and the loop for the latex tubing are basically rip-offs of what Ryan did except mine is made from a piece of PVC and a washer. (Thanks Ryan!) Also, used a CPT as they are functionally the same as Kane's snapoid trigger.