Paintball

[CJOttawa]

EDIT - alright, I changed my tune. I am now suggesting a slight valve modification. See my last post below: Redux Efficiency: Valve Modding

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Don't panic. I'm talking about a plastic insert, not modifying the Redux valve.

I read this thread and I'm a bit obsessed with this project so I'm starting this thread.

Efficiency problems/challenges with the DD68 Redux are due to two factors:

1. The stock barrel is 6.25 inches long
2. The in-handle 12-gram is pointed almost directly at the vent holes

I'm leaving point #1 for another thread. To illustrate the second point, see this photo:



You can see, with the pierce-pin assembly removed, the brass cup seal is peeking through.

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I've borrowed a section of Russc's diagram from the linked thread which shows a theoretical "insert" that would give the CO2 a longer path before getting to the powertube:



Issues when designing a valve insert:

• adding significant distance for the gas to travel
• not interfering with the cupseal or spring
• not scratching the valve internals

Wood or plastic would the ideal materials due to availability and ease of machining but there needs to be space between the valve inner wall and cup seal or the sleeve would be too thin to be strong.

My thought:

• OD of the insert would match the ID of the valve, preventing movement which could interfere with valve internals
• a groove would be cut around the OD of the insert, coinciding with the air inlet
• channels would be cut longitudinally down the OD of the insert to channel gas flow back
• another groove would be cut around the OD, closer to the rear and holes drilled through to let gas flow into the valve and forward to the powertube

Smiley already created a brass insert, however, there are several challenges with this approach:

• brass is more difficult to work
• the insert must be aligned correctly for gas flow since it's not symmetrical

A symmetrical, plastic sleeve wouldn't need to be aligned, it would work in all orientations.
I need to do some measurements to see if there's room enough between the cup seal and valve sides to allow for a sleeve. If not, plan B.

[russc]

I think that diagram is a little too constrictive, but the idea is sound from what I've tried. Smiley's design looks great, but you could probably afford to put more porting into it. You just want to stop the instant loss of liquid through the cupseal from the pierce pin assembly, while still allowing the valve to seal properly.

[splattttttt]

Building an insert that acts similar to an expansion chamber shouldn't be to hard to do.

[russc]

Well, it isn't so much an expansion chamber so much as a blocking or redirecting device, because there is a very specific area where we want to block the liquid while still allowing decent flow through the valve. It's not that we want more expansion, seeing as the valve has a decent amount of space as is. We just want to stop the liquid from skipping the valve entirely.

[splattttttt]

The design of the insert as to how it works for re directing air/liquid is brilliant.
I definetly wouldn't nock it down.
I'm just wondering if by adding a seperate insert wit in it, making operate similar to an X chamber is worth looking into?

[russc]

Just remember that there is a valve spring inside the insert, not a whole lot of room to work with.

[DSA]

You guys do know Steve is having better luck "over boring" the well as oppsed to restricting it. Based on the overboring theory one could come to the conclusion that adding a micro guage in the rear of the valve well might give you that extra needed space. I have measured one and it fits quite nicely under the slide when cocked rearward.

[CJOttawa]

Well, I had a crazy idea.

If there's no room in the valve for an insert to channel the gas, we're pretty sure there is enough "meat" in the valve to bore it out, since mOngo does that already.

We could mill a channel from the pierce pin area toward the rear of the valve, then insert a thin metal sleeve to redirect the gas.

This avoids the problem of interference with the cup-seal and spring by not requiring a thick sleeve!

[russc]

I'm not sure milling a channel would be feasible, since you would probably cut through the sealing face and valve threads on any operation like that. However, boring it out and then adding an insert would probably help the gun seal properly.

[CJOttawa]

Originally Posted by russc

I'm not sure milling a channel would be feasible, since you would probably cut through the sealing face and valve threads on any operation like that. However, boring it out and then adding an insert would probably help the gun seal properly.

I know what you're getting at.

I was thinking of a specialized cutting tool that had a smaller shaft/larger cutting head. The tool would be inserted past the threads so only the head touched metal.

The threads for the valve seat would have to remain untouched.