[Spitlebug]

Here's what I was getting at:

Comparison of just the Y vectors (as those are the only ones that are comparable in this case) reveals that indeed the additional 9" of length over a standard barrel does make a difference. The reason why we cannot look at the X is due to gravity and velocity changes. Does it mean it's practical or efficient to use a 21" barrel? Probably not. This doesn't really have anything to do with a flatter trajectory if you discount the X axis.

[Millertime]

Chris Logan, on Mar 23 2009, 06:53 PM, said:

Something that cockerpunk has been trying to point out is that a 10" one piece barrel had almost the same vector as the 21". Too little of a difference, in fact, to consider it different at all with the scope of the test.

Cockerpunk: Did you test using DXS frostbite on the one piece and DXS Silver on the two piece? Or is that a typo?

I firmly believe that there needs to be a testing standard, and this isn't it. By using paintballs at all, you are introducing far too many variables into a BARREL test. And then what about a the gun? The gun itself has it's own set of inconsistencies.



If barrel testing was done with a standard tool, at some point you can estimate how inconsistent the tool is. Same with projectiles. Remember the hard plastic target rounds that were available before all manners of foam balls? Those may be a good candidate. Extremely consistent in size. There is a seam. I'm not sure about how close in weight they are to the standard for paintballs.

Punkworks does an amazing job at testing these things. But the tests need to be totally repeatable. So that someone in Canada can set up the same test with a new barrel, and add to a large dataset. So that a new manufacturer can advertise and verify on this scale.

Here was the original question: What makes one paintball gun barrel better than the next?

And we still don't know.

I will agree and disagree with you Chris. I think that using plastic rounds to figure out the most accurate barrel would be irrelavant in this situation seeing as how that is not what is used on the fields. I think what all this testing has shown us is that we need not to worry what the most accurate barrel is, but we need to find a way to make paintballs more consistent in size, shape, and weight because those are what really affect accuracy. After figuring out a way to standardize those variables, is only when we can really start testing which barrel is the most accurate. That is my take from this experiment.

[brycelarson]

Chris Logan, on Mar 23 2009, 05:53 PM, said:

Something that cockerpunk has been trying to point out is that a 10" one piece barrel had almost the same vector as the 21". Too little of a difference, in fact, to consider it different at all with the scope of the test.

Cockerpunk: Did you test using DXS frostbite on the one piece and DXS Silver on the two piece? Or is that a typo?

I firmly believe that there needs to be a testing standard, and this isn't it. By using paintballs at all, you are introducing far too many variables into a BARREL test. And then what about a the gun? The gun itself has it's own set of inconsistencies.



If barrel testing was done with a standard tool, at some point you can estimate how inconsistent the tool is. Same with projectiles. Remember the hard plastic target rounds that were available before all manners of foam balls? Those may be a good candidate. Extremely consistent in size. There is a seam. I'm not sure about how close in weight they are to the standard for paintballs.

Punkworks does an amazing job at testing these things. But the tests need to be totally repeatable. So that someone in Canada can set up the same test with a new barrel, and add to a large dataset. So that a new manufacturer can advertise and verify on this scale.

Here was the original question: What makes one paintball gun barrel better than the next?

And we still don't know.

Our theory on this is that by using fresh, constant paint on the barrels we're locking down the paint variable better than pretty much any other situation in paintball. yes, the paint has a huge impact (maybe the largest) on many of our tests - but we're controlling better than most people do during play. If we had to go so far as to sort the paint by size, weight etc then shoot paint only in a slot - then we would be getting better barrel information - BUT, and this is a big BUT, what we find wouldn't really be any use for playing paintball - would it?

We use paint only a few days out of the factory by a good manufacturer.

you bring up a great point - we've done a ton of testing on a bunch of stuff - and all we can say about barrels is the following: underbore is more consistant and more efficient, blow through test is least consisteny, overbore is less efficient and good on consistency.

We CANT really say anything about accuracy or what the best barrel is. I'll say it again - the fact that we DONT see anything significant here is really the most interesting. If there were going to be a better barrel we would ahve seen it here. We shot at a significant distance, we shot in a controlled environment, we shot with a really good shooting gun clamped into a shooting bench. We shot really fresh paint from a good manufacturer. Yes, there were slight differences between barrels - but no significant trend (to my eye at this point).

[cockerpunk]

Chris Logan, on Mar 23 2009, 05:53 PM, said:

Something that cockerpunk has been trying to point out is that a 10" one piece barrel had almost the same vector as the 21". Too little of a difference, in fact, to consider it different at all with the scope of the test.

Cockerpunk: Did you test using DXS frostbite on the one piece and DXS Silver on the two piece? Or is that a typo?

I firmly believe that there needs to be a testing standard, and this isn't it. By using paintballs at all, you are introducing far too many variables into a BARREL test. And then what about a the gun? The gun itself has it's own set of inconsistencies.



If barrel testing was done with a standard tool, at some point you can estimate how inconsistent the tool is. Same with projectiles. Remember the hard plastic target rounds that were available before all manners of foam balls? Those may be a good candidate. Extremely consistent in size. There is a seam. I'm not sure about how close in weight they are to the standard for paintballs.

Punkworks does an amazing job at testing these things. But the tests need to be totally repeatable. So that someone in Canada can set up the same test with a new barrel, and add to a large dataset. So that a new manufacturer can advertise and verify on this scale.

Here was the original question: What makes one paintball gun barrel better than the next?

And we still don't know.

your dancing around the point i was trying to make before when someone posted a similar statement.

if we control the paintballs themselves to a higher degree then anyone ever does when they play paintball (which due to our connections and sponsorship deals we can), and it looks like the paintballs are still the number one source of error, what does that tell us about barrels?

it tells us the effect of barrels (size, length, bore, porting pattern, cost ...) has a smaller effect then the paintballs themselves.

put a different way, if under controlled conditions the largest effect we can see is error due to paintballs, then what difference does the barrel make when your in the heat of a gunfight, or running and gunning with all those associated errors?



as for standardizing tests, this test is repeatable, just make sure that to confirm out findings you do a benchmark test with your gun and your paint with a barrel we used in our testing. that should give you a correction factor for all the other errors with which you can modify your own collected data.

and, as i stated before, that is a typo which i have fixed but for some reason google docs has not updated.

This post has been edited by cockerpunk: 23 March 2009 - 07:17 PM

[cockerpunk]

conclusions video up - http://www.youtube.c...h?v=4FfmGo9mIwE

[wgp2002]

i wonder if the first strike rounds will show more of a difference in barrels than regular paintballs. the polishing on the inside of the barrel would seem to be more in contact with the round than a standard paintball

[Leafy]

i have a feeling that you could shoot the first strike rounds through pvc pipe of fairly close bore match and still have it shoot mint, in other words I'd hypothesize that the barrel has no effect on the fs rounds (ie even the triable barrel would shoot them nice)

[wgp2002]

well pvc pipes are damn smooth but i get what you are saying.

[Leafy]

wgp2002, on Mar 25 2009, 08:41 PM, said:

well pvc pipes are damn smooth but i get what you are saying.

where do you get your pipe? all the pipe I have for my air launchers have crazy dimples on the inside.

[wgp2002]

um the local hardware store.. ive never noticed any real major dimples in mine.

[Snipez4664]

Leafy, on Mar 25 2009, 08:22 PM, said:

i have a feeling that you could shoot the first strike rounds through pvc pipe of fairly close bore match and still have it shoot mint, in other words I'd hypothesize that the barrel has no effect on the fs rounds (ie even the triable barrel would shoot them nice)

I suspect this is almost completely incorrect! EDIT: and the tribal test results suggest I am right.



I have a serious problem with the characterization of vortex shedding in the video. The roundness of the paint won't save you to any degree worth mentioning...the vortex shedding is sequential, not simultaneous, so there is ALWAYS a net force. This leads to a random walk, no matter what you do, and you can in fact predict a gaussian distribution (it was done once upon a time in deep blue) for the pattern. I make this a point of contention, because if you think off-roundness has something to do with it, your natural inclination is to expect rifling to make a difference. However, if you look at the shift in surface velocities induced by even the most aggressive rifling, its trivial to see that vortex shedding should still be random and with an angle that is still essentially perpendicular to ball flight (bad!).

This reinforces the notion that when launching imperfect spheres (see: baseball, golf, ping pong, tennis), spin is key not only to trajectory (Magnus effect), but possibly to precision as well - if you control the spin variable not only do you control the magnus forces, but perhaps you create node for the vortices to preferentially shed from, at least along one axis.

This post has been edited by Snipez4664: 25 March 2009 - 08:42 PM

[cockerpunk]

Snipez4664, on Mar 25 2009, 09:22 PM, said:

Leafy, on Mar 25 2009, 08:22 PM, said:

i have a feeling that you could shoot the first strike rounds through pvc pipe of fairly close bore match and still have it shoot mint, in other words I'd hypothesize that the barrel has no effect on the fs rounds (ie even the triable barrel would shoot them nice)

I suspect this is almost completely incorrect! EDIT: and the tribal test results suggest I am right.



I have a serious problem with the characterization of vortex shedding in the video. The roundness of the paint won't save you to any degree worth mentioning...the vortex shedding is sequential, not simultaneous, so there is ALWAYS a net force. This leads to a random walk, no matter what you do, and you can in fact predict a gaussian distribution (it was done once upon a time in deep blue) for the pattern. I make this a point of contention, because if you think off-roundness has something to do with it, your natural inclination is to expect rifling to make a difference. However, if you look at the shift in surface velocities induced by even the most aggressive rifling, its trivial to see that vortex shedding should still be random and with an angle that is still essentially perpendicular to ball flight (bad!).

This reinforces the notion that when launching imperfect spheres (see: baseball, golf, ping pong, tennis), spin is key not only to trajectory (Magnus effect), but possibly to precision as well - if you control the spin variable not only do you control the magnus forces, but perhaps you create node for the vortices to preferentially shed from, at least along one axis.

well number 1 - im not gonna try to teach a fluid mechanics course in 10 minutes. i tried to do this video with more detail but it went long, hence the annotation near the end. there is only so much you cram in there and that 14 year olds will understand.


secondly, yes, i understand and agree that you are right, at any given TIME, there is a net force. but, if we look though time, and sum the forces, in theory, they should even out. or even out within a normal distribution.

however, if we are shooting a less then perfect sphere, then the sum of forces though time wont be as normal. or more accurately will lead to a larger normal. this is because the random walk will not truly be random, it will change depending on the profile of the boundary layer. when im thinking non spherical im thinking elliptical or even dimples.

as for spin, we have seen its effects for the most part. and after we have some high speed, we should be able to see its effects better.

i get what your saying, i do. maybe if people have alot of questions, then i will do a video purely on vortex phenomena. i tried to make it as simple as possible, not confuse people.

This post has been edited by cockerpunk: 25 March 2009 - 09:03 PM

[Snipez4664]

I understand that constraint, which is why I posted here rather than crafting a video response. The important note is that even if you had THE perfect paintball, with NO spins or course deflections or wind whatsoever, you'd still get inaccuracies that are a majority of the ones you reported. Obviously deformities lead to large confounding forces - ball quality and gun cleanliness are probably the biggest things your average player can control.

[cockerpunk]

Snipez4664, on Mar 25 2009, 10:38 PM, said:

I understand that constraint, which is why I posted here rather than crafting a video response. The important note is that even if you had THE perfect paintball, with NO spins or course deflections or wind whatsoever, you'd still get inaccuracies that are a majority of the ones you reported. Obviously deformities lead to large confounding forces - ball quality and gun cleanliness are probably the biggest things your average player can control.

yup! thats why i suggest high quality paint.

i mean your going to get a distribution under even the best conditions. but getting good round paint that is clean and a consistent setup thats about the best you can do. there isn't really any magic in the whole thing. besides giving consistent initial conditions, the barrel can do little to improve consistency.

[Lord Odin]

It's results like these that make us want to change the nature of the beast (damn, that's twice I've used that phrase in one day). If all barrels are going to perform similarly and paint is going to do it's own thing, then perhaps the paint is what needs to be changed. Hopefully that's where First Strike will come in. This Summer, I'm hoping to have my target completed and have some rounds in my hands to do some accuracy tests of my own. I'm sure you guys can put them to the test before then.

[paintballpdh19]

english???

[Spitlebug]

paintballpdh19, on Mar 25 2009, 08:45 PM, said:

english???

They are basically talking about the fact that if a ball was perfect no matter how you shot it with a paintball marker there would still be some randomness to the strike of the paintball on the target due to what is called "vortex shedding". Essentially "vortex shedding" is how the paintball flies through the air and how it moves that air around it.

This post has been edited by Spitlebug: 25 March 2009 - 11:39 PM

[CrazyLittle]

paintballpdh19, on Mar 25 2009, 08:45 PM, said:

english???

When you're riding in the passenger seat of a car and you hold your hand out the window like a wing... No matter how perfect or flat or round or even or aerodynamic your hand is, the wind will knock your hand around. That's a gross oversimplification of vortex shedding, but what they mean is this:

Both the imperfections in the roundness of the ball, and the effects that AIR has in knocking the ball around, will have far more effect on accuracy than any barrel could.

[Jack Wood]

Snipez4664, on Mar 26 2009, 01:22 AM, said:

Leafy, on Mar 25 2009, 08:22 PM, said:

i have a feeling that you could shoot the first strike rounds through pvc pipe of fairly close bore match and still have it shoot mint, in other words I'd hypothesize that the barrel has no effect on the fs rounds (ie even the triable barrel would shoot them nice)

I suspect this is almost completely incorrect! EDIT: and the tribal test results suggest I am right.



I have a serious problem with the characterization of vortex shedding in the video. The roundness of the paint won't save you to any degree worth mentioning...the vortex shedding is sequential, not simultaneous, so there is ALWAYS a net force. This leads to a random walk, no matter what you do, and you can in fact predict a gaussian distribution (it was done once upon a time in deep blue) for the pattern. I make this a point of contention, because if you think off-roundness has something to do with it, your natural inclination is to expect rifling to make a difference. However, if you look at the shift in surface velocities induced by even the most aggressive rifling, its trivial to see that vortex shedding should still be random and with an angle that is still essentially perpendicular to ball flight (bad!).

This reinforces the notion that when launching imperfect spheres (see: baseball, golf, ping pong, tennis), spin is key not only to trajectory (Magnus effect), but possibly to precision as well - if you control the spin variable not only do you control the magnus forces, but perhaps you create node for the vortices to preferentially shed from, at least along one axis.

That's what I was trying to say in the (one of man) discussion we had on this subject in another thread. Was it the Hammerhead thread? Preferential shedding.

So, how do we try and get a look to see if this really happens? I feel that even a very slow rotation that is near-perpendicular to the axis of flight could lead to small degrees of preferential shedding. Some college geek somewhere must have written a paper on the influence on vortex shedding in rotating spheres in a flow.........

[cockerpunk]

if you haven't already, you gotta check out the first video showing vortex shedding.

this guy is using lazes to illuminate micro hydrogen bubbles to see the flow. its freakin sweet.