Paintball

[CJOttawa]

Problem
The DD68 Redux design is such that you run the risk of pinching paint between the snub and slide.

Out of the box, pump technique is critical to counter the design flaw.

If paint is crushed while pumping, shell and fill will likely contaminate the gap between slide and snub, possibly jamming the gun entirely and almost certainly fouling any subsequent paint, causing erratic shots.

In short: pinching or crushing paint will most likely make the gun unusable until thoroughly cleaned.

You can read a full review of the DD68 Redux here: DD68 Redux [NO HOLDS BARRED] Review

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The Cause
The cause of the pinched and crushed paint is summed up well by Splattttttt, citing a single photo:

Originally Posted by splattttttt

He're the problem CJ...

Add a ramp that is flush with the snub...

Breech drop allows half of a second ball to feed into the breech. A detent will NOT stop this; ball 2 is sitting on top of ball 1, as shown in this photo, without the feedblock installed:


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Prevention Strategies
Unmodified, pinches can be prevented by tilting the gun back and away from the feed tube.

The feed block has enough of a "shelf" to hold a single paintball above the breech, allowing the remaining paint to roll back down the feed tube. This will not work if you overload the feed tube; there needs to be a one ball gap.

DSA has a pump technique that works with larger (0.680+) paint.
He details it in his reply below, linked here: http://www.mcarterbrown.com/forums/r...ml#post1639724
His YouTube video is linked here: YouTube - Redux Loading Technique

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Technical Solutions
WK2, PMI 3 and others noted the DuckSlide has a "ramp" behind the feed port, shown in this photo:

Originally Posted by WickedKlown2

...DuckSlide in the closed position with the rear to the left side of pic

...

PMI 3 indicated he'd never pinched paint on his DuckSlide, suggesting the ramp does prevent pinches.

Milling the Slide and Feed Block

Milling the Redux slide and feedblock to mimic the ramp on the slide of the DuckSlide solves the pinch problem.

After the mod, Mar and I ran 20-30 paintballs through the modified Redux and it didn't pinch.
We clearly saw the second ball being "scooped" - to borrow PMI 3's term - out of the breech.

The Redux, with this modification, was even auto-triggered without pinching.


The Milling Process
With all of the above background information, I took the risk of making the modification.

1. Remove the slide from the snub and the feed block from the slide.
2. Mark a 45-degree point on the rear of the slide's feed port; this is the thickest part of the slide.
3. Use a small, rat-tail file to start the bevel.
4. Work slowly.
5. Once the channel is cut to about half the desired depth, switch to a larger round file or use a milling cutter or tubular sanding tip on a rotary tool.
6. Work slowly.
7. Test fit the slide to the snub with TWO paintballs; once you achieve the correct bevel/ramp, the second ball should pop out of the way.
8. WORK SLOWLY!
9. After the slide bevel has been cut, re-install the feed block and mill, grind or file down the rear of its feed port until it's a smooth continuation of the slide bevel, taking care not to cut into the slide.
10. Once the block bevel matches the slide, remove it and install the feed tube.
11. Mill out the feed tube port to match the block.
12. Polish the machined sections; I started with 400 grit wet sandpaper and moved to 1500 grit.
13. Finishing touches: have the now-unusable rear screw hole filled; I'm looking in to a precision aluminum welder for this but epoxy steel could work too.

A photo montage of the milling process follows, starting with the mark made in step 2 and the rat tail file used in step 3, above.




The slide now has "anti-pinch" properties, similar to the DuckSlide. At this point, it can be smoothed and work started on the block.



Feed block milling underway.




Feed block and slide bevel smoothed out, initially with rotary tool, then 400 and 1,500 grit sandpaper.



Feed tube milled to match the block, allowing paint to drop and be "scooped up" farther back than with the stock, circular port.







Conclusion
With the slide and feed block milled with a smooth ramp, the second paintball, resting partly inside the breech, on top of the first paintball, popped up, "scooped" as PMI 3 put it, and didn't pinch.

HUGE THANKS go to:

• Canuck - close friend and source of much sage advice, technical and otherwise.
• Splattttttt - for participating in this discussion, despite not owning a Redux, and correctly identifying the major cause of the problem and the solution, the rear of the feed block which was crushing the paint against the snub's feed port.
• Dukie - for the face time and input on the problem, and the sneak peek of the DRV's.
• IronChef97 - for the multitude of discussions we've had about the evolution of the DD68 and the design features shared and different between models, as well as the extensive photo library that helped identify the problem area and possible solutions.
• WickedKlown2 - for the photos of the DuckSlide and discussions of the design problem.
• DSA - for playing the "challenge" role in this discussion, forcing me to think things through carefully.
• Mongo - for making the Bugatti Veyron of stock class markers!
• ...and everyone else who engaged in the discussion about this very specific design challenge.

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Feed Mod Revision 2

I noticed a possible binding issue with the feed system. It used to happen, pre-milling, but couldn't be fixed because it would have left too small a path for the balls to feed. (sub-0.68cal).

The solution: a parabolic profile ahead of the horizontal feed.

Diagrams below.

DD68 Redux Feed Port






A video of Redux 043 with this mod, chambering ten rounds, is now online:

[ironchef97]

Originally Posted by cjottawa

You are indeed uniquely qualified to address this!

Any thoughts on how we might improve the DD68 Redux?

I didn't want to come off sounding like I know everything hahaha, actually Mongo also would have a good perspective on this situation as well..


Anyways, from my examination of the differences between the Carter body and Redux slides, there are pros and cons to both.

Redux:
-easy to clean hits in the feedtube since you can take it apart.
-easy to clean ball breaks from pinches.
-when removing the slide from the snub/frame, you don't have to remove the feed cap

-feed tube is farther away from the body, so it doens't look 'as good' + it's possible the balls can stack on top of each other (depending on how much of your snub was shaved off to reduce pinching). my snub has less shaved off than DSA's for example. However, this may actually be better, because less balls will 'stack' on top of each other. Although honestly, the most that could stack is 1/2 a ball, or 1/3 of a ball.

Duck:
-extremely hard to clean hits that get dirt/paint into the feedtube area. Some ducks have an additional piece of curved metal where the feed tube/body mate, you can see it on flyingpootang's duck. Mine were missing this 'feature'. It's pretty rare that you'll see a hit in this area, but it can happen (and has).
-You have to remove the feedcap everytime you want to take the slide off, you can dent the feedcap on the snub if you forget, when you pull the slide forward after the latch is removed.
-However, the feedtube is so close to the slide, that you can see part of the slide was milled out for the feedtube to rest in. Also, the shaved part of the snub is shaved really thin, so thin that you could actually slice balls in half if you so desired, rather than just pinching them. I have never sliced a ball though, and the thinness of this portion of the snub allows for very little pinching. Plus the proximity of the feedtube and the large shaved portion of the snub allows a 'resting' spot for 1 ball to sit, but no more.
-Looks a lot better in my opinion .




In my opinion, the shaved snub was a feature developed for the original 'Shooters, because they all had direct feeds. The shaved portions on those are also very thin. When you have 10 balls stacked up, you can quickly see why an almost razor thin shaved snub is vital to feeding without pinches.

With the development of the stock class feed slide, these snubs were still important, but in a different way. You have to develop a different way to pump...the way you described CJ.


With SC feed slides, sometimes I find that pinches occur due to the 2nd ball in the tube getting caught between the snub and the slide, rather than the first.


**One last interesting thing to note is that original kamikaze shooters with welded feedtubes have their feedtubes spaced somewhat inbetween Carter ducks and Reduxes...BUT if you look closely, there is a small slot on Loo's duck, where balls can drop down to the body level sooner.
[IMG][/IMG]
I have no idea whether this is a unique thing, or if all the original 'shooters had this 'enlarged' feed port.

Check out these other pics...

[mOngo]

VERY good!!!!!!!!! that about sums it up- my next Redux will be called "Blue Badasseryness" and this will be engraved on it after anodizing in Papyrus font. This also reminds me of a day of play at Challenge Park in Memphis TN when the guys who walked past my dd68 and I sitting on a picnic bench exclaimed- "hey buddy, that's a nice gun, but the shooting range is up the road a bit......... this is a paintball field"

[CJOttawa]

UPDATE: DON'T fill the feed tube to the maximum capacity.
Doing so will put a second ball over the feed block and probably result in a double feed and very messy pinch.

It's much easier to prevent pinches tilting the gun back to cock rather than trying to rapidly pump to prevent a double feed.

Loading to 12-13 balls in the Redux feed tube: baaaaad idea.

I'll test this later and see "how many is too many".

I think 11 is fine since there's room for ball #2 to roll away from the feed port.

[splattttttt]

I've never actually seen a Redux, and although I really admire their look, I'm not quite familiar with its functionality.
I've owned Duckslides before, and never pinched, or copped a ball with them ever.
But when I'm envisioning an occuring pinch/chop, what generally comes to mind is a coldcut slicer.
Lower the tray for a fatter slice, raise the tray for a thinner one.
I think the balls resting on top of the bolt just fine... Where else should it be lol.
It's when the stroke is returned forward, that something is slicing the ball.
So what ever is coming forward either needs to be lower, or the snub is too fat of an OD, thus making it difficult for the ball to gently move back up.

[ironchef97]

Originally Posted by DSA

Hey Iron would you say it's the slide not the snub or feed tube? That being said does the lower profile "glued" on feed tube Carter Duck also bind a bit? From what I can tell it's the meat of the slide thickness not the stack of the balls.

Hm, I would say its both the slide and the snub. While the redux 1.1 snub upgrade helps, there is still more that could be shaved off. If you get the chance to look at the snub of a duck, there is a LOT of meat milled off.

Gluing the feed tube to the body has removed some material which the second ball could be pinched by. Alas, I have been bitten by the custom sheridan bug as of late, and have not taken my duck out for a spin .

[CJOttawa]

Thanks for stopping in Have Blue. I didn't want to speak for you in case you wanted to keep things on the QT.

A couple of my observations:

1. the Redux pinches because more than one ball falls into breech and...
2. the second ball can't easily move back out of the snub when the slide is moved forward (double-feed & pinch)

Have Blue/ASP is addressing #1 with the Phantom o-ring detent mod.

Another issue I've been wondering about: the feed block is machined using a ball end mill. Instead of a power-feed style "parabolic" turn for the ball stack to bend around, there's a very nice ball-shaped TRAP for paint to snag in when being pushed back.

I truly don't know if this a factor but I suspect it COULD be preventing paint from moving out of the way when the slide moves forward.

I would be interested in adding a bit of a parabola to the feed block to see if it allows paint to move back up the tube more easily.

[splattttttt]

Frankly, I think there's just too much distance between the feed and the receiver. I know I said it before.

[DSA]

Ok sorry for the poor quality but you have to understand I'm traveling lite, iPhone,iPad,MacBook, Army gear, poogie bait and redux. So here you go, I'm not going to say I haven't experienced the bindin on a few occasions because I have. I will say however it's not something people should get wrapped around the axels about. The design is what it is, an original copy of the DD68 with today's upgrades. It's going to happen but not mainly due to design bit rather paint.

YouTube - Redux Loading Technique



An oblong ball will cause it to happen as will the tiny little balls up north. My advice is simple use the Redux ball sizer, pick your paint as carefully as you pick your shots and just pump it normally at any rate you desire.

[splattttttt]

Originally Posted by DSA

Hell Jack I'll be 45 this year everyone is a kid to me.

If life had been more advantagious for me, I could have a son walking this earth who would be the same age as you are now lol