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so what actually cuases barrel breaks?


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#1 cockerpunk

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Posted 30 October 2008 - 05:14 PM

a continuation of the discussion we were having earlier this month.

my question ...

i get barrel beaks with a pump gun - why?

i know they are not chops, because i can feel that, but i do get barrel breaks. does anyone have a theory as to why?
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#2 Nicholai

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Posted 30 October 2008 - 05:30 PM

Edited for stupid content, wasn't aware of who cockerpunk was at the time.....

Edited by Nicholai, 18 November 2008 - 06:12 AM.

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#3 Leftystrikesback

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Posted 30 October 2008 - 05:49 PM

The easiest answer is that your paint isn't perfect, it has some surface flaws that create stress concentrations when the force of the air blast hits it.

Categorizing the surface flaws is more of a chore, I would say the worst kind is what you see in "bad paint," such as dimples, oblong shape, or inconsistent wall thickness.

Obviously no paintball is a perfect sphere with isotropic surface properties (constant everywhere). For one thing each has a stiff seam, which likely increases stress concentrations to either side of the seam.

I start it off with that.
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#4 cockerpunk

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Posted 30 October 2008 - 07:02 PM

in all my pumps, with all the different barrels (and bores) i have had barrel breaks.
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#5 ChrisB

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Posted 30 October 2008 - 07:16 PM

My guess is that its the paint. Even if you got the best paint there's gonna be surface defects or stresses. Maybe not noticeable to the eye but it's there.

But that's just my 2 cents.
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#6 Leftystrikesback

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Posted 30 October 2008 - 08:49 PM

Speaking of paintballs and stresses, does anyone have or know where I can get some material properties of the gelatin that paintball shells are made of?
Even if you knew a more specific name for the gelatin mixture that they are made out of that would help my searches for the material properties, "gelatin" doesn't turn up anything useful on google or in a library search.

I'm going to see if I can set up a FEA model to show how paintballs might deform in a barrel, and if stresses occur around a seam.
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#7 brycelarson

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Posted 30 October 2008 - 09:44 PM

Speaking of paintballs and stresses, does anyone have or know where I can get some material properties of the gelatin that paintball shells are made of?
Even if you knew a more specific name for the gelatin mixture that they are made out of that would help my searches for the material properties, "gelatin" doesn't turn up anything useful on google or in a library search.

I'm going to see if I can set up a FEA model to show how paintballs might deform in a barrel, and if stresses occur around a seam.


first I'm going to say - it's all the paint.

I think that any hope of alleviating barrel breaks through bore choice is a false hope.

and in direct answer to your question - my guess would be is that each manufacturer has their own formula for shell and fill. I'm pretty sure that they are secretive - but, as CP and I have found - paintball manufacturers can be cool. I suggest you spend a couple hours on the phone and call some companies. These are small businesses - and it's likely that they might help you out. Might not give exact formulas - but maybe they would be helpful with information that would make your math a good addition to the work we're trying to do in PunkWorks.

#8 cockerpunk

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Posted 30 October 2008 - 09:59 PM

already on the phone with joey again for the compression test ;)
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#9 Troy

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Posted 30 October 2008 - 10:55 PM

Speaking of paintballs and stresses, does anyone have or know where I can get some material properties of the gelatin that paintball shells are made of?
Even if you knew a more specific name for the gelatin mixture that they are made out of that would help my searches for the material properties, "gelatin" doesn't turn up anything useful on google or in a library search.

I'm going to see if I can set up a FEA model to show how paintballs might deform in a barrel, and if stresses occur around a seam.


I would be very interested in this. You may have better luck trying to figure out the exact ingedients by looking at the back of a NyQuil box, or some other kind of gelatin capsule.

What kind of property info do you need? If we have the answer to that, we may be able to organize some tests to get this figured out.

I imagine that we'll be able to get some kind of model that is close enough to test with that can shed some light on what causes breaks without knowing THE EXACT formula each manufacturer uses.

If it absolutely comes down to it, I can get ahold of a flame emission spectrograph and figure out the exact molecular composition of that damn shell... but I would rather not if its at all possible.
\m/

#10 cockerpunk

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Posted 30 October 2008 - 11:09 PM

I would be very interested in this. You may have better luck trying to figure out the exact ingedients by looking at the back of a NyQuil box, or some other kind of gelatin capsule.

What kind of property info do you need? If we have the answer to that, we may be able to organize some tests to get this figured out.

I imagine that we'll be able to get some kind of model that is close enough to test with that can shed some light on what causes breaks without knowing THE EXACT formula each manufacturer uses.

If it absolutely comes down to it, I can get ahold of a flame emission spectrograph and figure out the exact molecular composition of that damn shell... but I would rather not if its at all possible.


damn punkworks is awesome!

i think the compression test will tell us alot about how paintballs resist loading. me and bryce will take pictures if any kind of failure trend emerges (like we should have done on the barrel break test!)

FEA ... damn, thats a sweet idea!
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#11 Leftystrikesback

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Posted 31 October 2008 - 02:15 AM

The material properties I would need would be for the shell only and would be young's modulus, shear modulus, poisson's ratio, ultimate tensile strength. If we get some results from the compression test that was mentioned then I may be able to derive some of those values. I don't think the recipe or flame emission spectrograph will help, thanks for the offer though!

I did some work on the FEA model and figured out a plan:

What I want to do is show where the stress concentrations are on a stiff spherical shell filled with liquid when it's hit with a pressure along its rear half and constrained along its circumference (paintball held in a barrel hit with air).
If I get a base model for that then I'll start to look at what changes the stresses to a point where failure might occur:
I'll put a seam on it to see if that adds anything interesting. I'll make a bit of the shell thinner and see what happens to that part. Maybe I'll add a dimple, or make it more oblong... things like that in different orientations could lead to some insight into what defects in the ball contribute to barrel breaks. This model would be a static approximation of a dynamic action so it's limited by that and the assumptions made to constrain the model.

I can show stress concentrations on a spherical shell under similar loading circumstances, that part is not too difficult. I ran some models earlier today and got some results that are consistent with observation... however they aren't really valid since I haven't "filled" the shell yet.

For that I need to figure some stuff out with multi-body analysis I think, possibly wait a new software version my lab is getting soon.

If I only want to look at where the stress concentration's occur and ignore the actual forces at work, I can probably use any linearly elastic material so that's where I'm going to start.
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#12 Troy

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Posted 31 October 2008 - 08:01 AM

I don't think the recipe or flame emission spectrograph will help, thanks for the offer though!

That's kind of what I was thinking. It would only really help if we had to recreate the shell to test it. Unfortunately, knowing what its made of doesn't tell us it properties.

What I want to do is show where the stress concentrations are on a stiff spherical shell filled with liquid when it's hit with a pressure along its rear half and constrained along its circumference (paintball held in a barrel hit with air).
If I get a base model for that then I'll start to look at what changes the stresses to a point where failure might occur:
I'll put a seam on it to see if that adds anything interesting. I'll make a bit of the shell thinner and see what happens to that part. Maybe I'll add a dimple, or make it more oblong... things like that in different orientations could lead to some insight into what defects in the ball contribute to barrel breaks. This model would be a static approximation of a dynamic action so it's limited by that and the assumptions made to constrain the model.

I can show stress concentrations on a spherical shell under similar loading circumstances, that part is not too difficult. I ran some models earlier today and got some results that are consistent with observation... however they aren't really valid since I haven't "filled" the shell yet.

For that I need to figure some stuff out with multi-body analysis I think, possibly wait a new software version my lab is getting soon.

If I only want to look at where the stress concentration's occur and ignore the actual forces at work, I can probably use any linearly elastic material so that's where I'm going to start.


I think you're on to something. Like I hinted at before, the properties of gelatin may not be necessary to make broad assumptions along those lines. You may be able to use some other flexible material, like a plastic, or latex, that you have info for in substitution... that might shed some light on this.
\m/

#13 Leftystrikesback

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Posted 31 October 2008 - 12:54 PM

I've been using polypropylene in my models thus far. I'll post some if I have the time but it takes a while to describe the assumptions and what conclusions you can make.
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#14 moyster14

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Posted 31 October 2008 - 03:15 PM

Here's an off the wall idea to bounce off everyone. It goes beyond the forces applied to the paintball and its defects. The rapid expansion of gas propels the paintball, which can be considered an adiabatic process. This rapid expansion will absorb thermal energy and the paintball is right there next to the expanding gas. So could there be some localized cooling taking place that could effect the properties of the paintball? There already been quite a bit of talk regarding the refrigeration of paintballs and how they change with temperature, so there may possible be some interesting thermodynamic effects taking place as well.

Let me know what you all think.
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#15 Snipez4664

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Posted 31 October 2008 - 07:14 PM

As a chemical engineer, I doubt it. Gas is a terrible medium for heat transfer, and gelatin isn't much better. That and the contact time isn't very long at all. Go shoot a paintball into a tarp, and pick it up - I doubt it will be much less than room temp.
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#16 moyster14

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Posted 31 October 2008 - 07:44 PM

Well I didn't mean the paintball is going to have frost on it. I'm sure the paintball will be back up to temp by the time you touch it.

I'm talking about cooling on maybe only half the paintball, perhaps only the surface facing the bolt and very, very quickly. Maybe just enough to create a weak spot or enhance a surface defect. I'm just wondering if inducing a temperature gradient through the thickness of the shell plays a role. Especially with other forces acting on it. Now as an electrical engineer, I'm not too experienced with heat transfer and thermodynamics, I'm just throwing the idea out there. Plus there there may also be some heat produced through friction. Will any of the this contribute, maybe not, just thinking outside of the box. ;)
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#17 oerllikon

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Posted 09 November 2008 - 09:37 PM

Is there a such thing as an "Air Hammer" (Like a water hammer) could it be the air hitting the ball suddenly?
Or is it a weak wall on paint?
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#18 Eskimo

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Posted 10 November 2008 - 04:38 PM

Could it just be that murphy's law just doesnt want you to go without breaks?

Im thinking it might have to do with the position of the paintball and the acceleration of it.
(for viewpoint sake, looking out from the breech though the barrel and towards the target, the paintballs point of view)
If the paintball is ever so slightly to the left or right, ( so one side) and when it accelerates, ( which it does, greatly) the paintball hits the side of the barrel. when this happens the paintball begins to turn so if it hit the left side it rotates left. ( i think) and when that happens the paintball can do one of three things.
1. it makes contact to the barrel wall, creating the friction between ball and wall ( lets say an aluminum barrel) and the ball simply tears apart from the friction and the rubbing against the wall.

2. it bounces off, still roatating it hits the opposite wall creating an rotation on the other direction, this sudden stop and start causes the paintball to tear open and burst apart. ( so one side of the paintball is being mushed against the stopped portion ( against the wall) and the portion of the ball past the contact point still rotants to the left, this is the tear point, becuase of the streached material, especially if it is the seam)

3. it bounces off and leaves your barrel.

now of course this is assuming your paintball has a small amount of space down the barrel ( not extreme overbore.) but so you can slighltly blow it though. ( when a paintball is shot it changes shape, a little more oblonged.) <- as far as I know. when we do a blow test the ball is still a ball, when its fired extra space is created on the sides becuase it becomes more egg shaped due to acceleration.

thats just my thoughts on barrel breaks.
( But I still believe its murphys law.)

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#19 pb101

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Posted 10 November 2008 - 09:53 PM

Perhaps we should be asking the people who make paintballs. Maybe they might have some insight into this subject.

#20 brycelarson

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Posted 10 November 2008 - 11:02 PM

thats just my thoughts on barrel breaks.
( But I still believe its murphys law.)


All barrel breaks in our test were between 3/4 and 1.5 inches into the barrel - this indicates to me that the breaks were not from shear force or barrel interaction - more just the ball exploding on the contact of the burst of air.

This is held up by Simon's youtube video of the glass barrel and the ball break - it doesn't move, just "pops" in place.

glass barrel break

#21 ktap

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Posted 10 November 2008 - 11:16 PM

looking at manike99's glass barrel break on youtube, and Lefty's simulations on my paintball deformation thread, but more specifically his measurements of shell thickness, i would conjecture that the paintball always breaks along the seam. Chiefly for the reasons that A. according to lefty's measurements, the seam is thinner, and B. on manike99's vid the ball clearly broke along one side, not sure if it ws on the seam however, and C. paintballs are not perfectly round, and seem to have a larger diameter around the seam.

speculation however is bad thing, we need more data.

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#22 brycelarson

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Posted 10 November 2008 - 11:21 PM

looking at manike99's glass barrel break on youtube, and Lefty's simulations on my paintball deformation thread, but more specifically his measurements of shell thickness, i would conjecture that the paintball always breaks along the seam. Chiefly for the reasons that A. according to lefty's measurements, the seam is thinner, and B. on manike99's vid the ball clearly broke along one side, not sure if it ws on the seam however, and C. paintballs are not perfectly round, and seem to have a larger diameter around the seam.

speculation however is bad thing, we need more data.


that seems (no pun intended) likely.

the thing that seems to be very consistent is that mid-barrel breaks just don't happen. The barrel breaks seem to be either due to the force of the air, the inertial of the paintball or the static friction with the barrel - all happen at the moment of acceleration.

#23 ktap

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Posted 10 November 2008 - 11:30 PM

another possible reason, or contributing factor, for early barrel breaks could be the ramping in the barrel from the diameter of the bore to the diameter of the barrel.

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#24 Jack Wood

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Posted 11 November 2008 - 06:28 AM

All barrel breaks in our test were between 3/4 and 1.5 inches into the barrel - this indicates to me that the breaks were not from shear force or barrel interaction - more just the ball exploding on the contact of the burst of air.

This is held up by Simon's youtube video of the glass barrel and the ball break - it doesn't move, just "pops" in place.

glass barrel break


It does move! It moves quite some distance before it breaks apart. Unless I am looking at it wrong.
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#25 brycelarson

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Posted 11 November 2008 - 10:14 AM

It does move! It moves quite some distance before it breaks apart. Unless I am looking at it wrong.


I thought it looked like it moved about 1 ball-width into the barrel - I'll try to get in touch with Simon and get verification.

I thought that the first movement was the loading stage - then the ball basically smashed in place when the air hit it.

I'll post up when I hear back from Simon.

#26 Cpt.Insaneo

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Posted 11 November 2008 - 10:48 AM

I think it has to do with the ball bouncing around in the barrel.
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#27 ktap

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Posted 11 November 2008 - 01:53 PM

I think it has to do with the ball bouncing around in the barrel.



anything to back that up? what about underbored paintballs? I don't mean to be rude, but what is your reasoning?

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#28 Snipez4664

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Posted 11 November 2008 - 03:02 PM

Let's look at what we know (My conclusions italicized) :

All guns seem to incur barrel breaks. The rate at which this occurs may or may not be statistically significant. This suggests that the inertial acceleration and/or pneumatic hammer does not account for the phenomenom alone.

All guns impart roughly the same energy to the ball, and impart this energy with exquisite consistency. This suggests that the inertial acceleration and/or pneumatic hammer does not account for the phenomenom alone.

MOST guns reach a breech pressure of 60-90 psi. Low pressure peaks in the breech do not appear to prevent barrel breaks. This suggests that the inertial acceleration and/or pneumatic hammer does not account for the phenomenom alone.

Barrel breaks occur in overboring and underboring situations, with APPROXIMATELY the same frequency. This suggests that neither bouncing into sidewalls nor friction accounts for the phenomenom alone.

The forces acting on a ball traveling down a barrel, accelerated from rest are:

Air pressure (90psi max, lets say)

Acceleration/inertial effects (difficult to say, perhaps the fill's inertia concentrates pressure to the rear of the paintball, creating an elongation force. Off the top of my head I would assume this type of localized force is more destructive to a sphere than a compressive load.)

Friction (We need a coefficient AND a stress/strain curve to quantify this as a function of underbore.) A human lung produces about 1-1.3psi of pressure - an individual with a paintball and a freak kit could get use some data.

Tangential bore impacts (given the relative vector, I would say this is unlikely to be a large force)

That's pretty much it.

We know that a material will break when your application of force most relevant to it exceeds its rating. Simply put, this means that paintballs may have more than one failure mode, caused by different forces that aren't necessarily of the same magnitude. A smaller force in shear is often more destructive than a large force in compression (see: wood). And impact force that may seem trivial may be concentrated enough to fracture very STRONG and HARD materials (see: ceramics).

In any rate, we know that barrel breaks are statistically outlying events, but they must have a root cause. Forces that are applied very consistently are unlikely to cause barrel breaks in and of themselves. To me, I see the gun as likely to apply very consistent forces once the ball is seated in the barrel. This leaves the bulk of variability to the condition of the paint AS IT ARRIVES IN THE BARREL. That throws up a bunch of new variables:

Paint brittleness/temperature
Orientation of seam
Breech/bolt interface transition
Harshness of bolt on paint (see: original marq bolt)
Bolt clipping of the paintstack (see:cure bolt)
Ball impacting breech bottom
Loader torque/harshness


The question is, how do they conspire to break a ball? Is the ball just exceptionally weakened, or has the gun produced a particularly Herculean shot? And most importantly, how do I fix it?
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#29 cockerpunk

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Posted 11 November 2008 - 03:15 PM

wonderful snipez!

simon would be proud of that post. and i have been holding myself from saying something very much like that.
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#30 oerllikon

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Posted 11 November 2008 - 03:36 PM

Would a venturi bolt actually help?
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#31 brycelarson

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Posted 11 November 2008 - 03:44 PM

all great stuff except for one part:

"All guns seem to incur barrel breaks. The rate at which this occurs may or may not be statistically significant. This suggests that the inertial acceleration and/or pneumatic hammer does not account for the phenomenom alone."

I just don't have the data to know if this is true.

CP and I only tested one gun with a bunch of barrels for our test - and I've never seen any data other than anecdotal about guns other than the cyborg.

really great post.

#32 Snipez4664

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Posted 11 November 2008 - 04:08 PM

all great stuff except for one part:

"All guns seem to incur barrel breaks. The rate at which this occurs may or may not be statistically significant. This suggests that the inertial acceleration and/or pneumatic hammer does not account for the phenomenom alone."

I just don't have the data to know if this is true.

CP and I only tested one gun with a bunch of barrels for our test - and I've never seen any data other than anecdotal about guns other than the cyborg.

really great post.


Thanks, I'm crushingly bored at work!

I include that point because if there WAS a gun that definitively broke less paint, we'd know about it because the developer wouldn't shut up about it. In my PURELY ANECDOTAL experience, guns that run lower bolt pressures tend to break less paint. With the possible exception of the automag (and I was told that the ball was already seat in the barrel for that breech pressure test, which makes a lot of sense if you consider how it vents), the venting geometry for all guns on the market is basically the same. In other words, if we're going to insist on playing scientists on TV, I haven't seen a compelling reason (a preternaturally gentle gun) to attempt to test a different gun for breaks, with the possible exception of the Angel One, which made a big deal of this. (For those of you playing at home, low hpr AND lpr pressures, soft face bolt, comes stock with a VERY overbored barrel kit).

I was having a conversation with a tinkerer/all-around-smart-dude friend of mine, and I suggested making a bolt with a variable restrictor (basically a mini mag bolt) in the face to smooth out the pressure response to the ball. I'm not gonna use that idea in any of my stuff because frankly I think it's stupid and won't matter, so there, it is open source. :)

I certainly land on the side of "get the ball safely to the barrel" - you can see that in the most research intensive companies offering loaders that have a focus on being gentle on paint (my DXS pulse routinely smashed whitebox paint in the loader), along with the increased focus on soft face bolts.

Also, after viewing the slow mo, I feel like it is likely the seam is where breaks start - possibly due to stresses incurred during loading (ever drop a paintball on a hard surface and it just barely cracks the seam?). It also looked to me like the ball splatter started on 2 points 180 away from each other on the barrel. Difficult to say if thats always the case, your insights welcome.
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#33 cockerpunk

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Posted 11 November 2008 - 04:22 PM

i wonder though, is the A1 really any more gentle on paint then other guns?

it could easily be the same thing we saw with underboring vs overboring. if we think we get less barrel breaks, we "get" less barrel breaks.
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#34 o-baller

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Posted 11 November 2008 - 04:22 PM

Thanks, I'm crushingly bored at work!

I include that point because if there WAS a gun that definitively broke less paint, we'd know about it because the developer wouldn't shut up about it. In my PURELY ANECDOTAL experience, guns that run lower bolt pressures tend to break less paint. With the possible exception of the automag (and I was told that the ball was already seat in the barrel for that breech pressure test, which makes a lot of sense if you consider how it vents), the venting geometry for all guns on the market is basically the same. In other words, if we're going to insist on playing scientists on TV, I haven't seen a compelling reason (a preternaturally gentle gun) to attempt to test a different gun for breaks, with the possible exception of the Angel One, which made a big deal of this. (For those of you playing at home, low hpr AND lpr pressures, soft face bolt, comes stock with a VERY overbored barrel kit).

I was having a conversation with a tinkerer/all-around-smart-dude friend of mine, and I suggested making a bolt with a variable restrictor (basically a mini mag bolt) in the face to smooth out the pressure response to the ball. I'm not gonna use that idea in any of my stuff because frankly I think it's stupid and won't matter, so there, it is open source. :)

I certainly land on the side of "get the ball safely to the barrel" - you can see that in the most research intensive companies offering loaders that have a focus on being gentle on paint (my DXS pulse routinely smashed whitebox paint in the loader), along with the increased focus on soft face bolts.

Also, after viewing the slow mo, I feel like it is likely the seam is where breaks start - possibly due to stresses incurred during loading (ever drop a paintball on a hard surface and it just barely cracks the seam?). It also looked to me like the ball splatter started on 2 points 180 away from each other on the barrel. Difficult to say if thats always the case, your insights welcome.


So you are saying that the most important factors in barrel breaks occur before the ball is shot into the barrel.
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#35 Snipez4664

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Posted 11 November 2008 - 04:32 PM

So you are saying that the most important factors in barrel breaks occur before the ball is shot into the barrel.


That is my personal opinion, yes.

I have no opinion or data on the A1, I have seen the video of them shooting chilled hellfire though, it's pretty impressive. Joy started winning (more) when they started shooting iced paint through A1s, it increases effective range a ton (read: kill players off the break). Similar tests have become popular on pbnation.
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#36 TechPB-Mike

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Posted 11 November 2008 - 05:47 PM

Some of my theories-

1) CO2 breaks more paint than HPA. Shooting snow into the back of a paintball causes them to break apart alot more. If you have ever dry-fired against your hand with CO2, you'd see how badly it stings.

2) Your specific paint is too brittle or just bad paint. Do a drop test from waist high, 3 or 4 bounces from waist level off concrete is usually a good place to start

3) Are you sure you're not "pre-pinching" the balls with your pump stroke? If you pump the gun extremely fast, there is a very high chance you are causing the ball to scratch against the top of the breech when you load it into the barrel. Many times I've smoothed out the finished edge with my finger and some 1000grit wet/dry, to smooth out that edge to prevent the ball scratching against that edge. Basically you're manually "chopping" the paint with your quick pump stroke


Hmm thats all I can think of now....

#37 cockerpunk

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Posted 11 November 2008 - 05:57 PM

Some of my theories-

1) CO2 breaks more paint than HPA. Shooting snow into the back of a paintball causes them to break apart alot more. If you have ever dry-fired against your hand with CO2, you'd see how badly it stings.

2) Your specific paint is too brittle or just bad paint. Do a drop test from waist high, 3 or 4 bounces from waist level off concrete is usually a good place to start

3) Are you sure you're not "pre-pinching" the balls with your pump stroke? If you pump the gun extremely fast, there is a very high chance you are causing the ball to scratch against the top of the breech when you load it into the barrel. Many times I've smoothed out the finished edge with my finger and some 1000grit wet/dry, to smooth out that edge to prevent the ball scratching against that edge. Basically you're manually "chopping" the paint with your quick pump stroke


Hmm thats all I can think of now....


3. yes, with a hand directly connected to the bolt, you can tell when you are pinching a paintball.
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#38 oerllikon

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Posted 11 November 2008 - 11:50 PM

You probably loose a lot of sensitivity with the actual pump. Ive only owned 3 nelson pumps, no cockers. The only time i have gotten breaks, were with my SI. That had a tiny bore, and i was using VI. It definitely wasnt a chop, because i saw the ball get loaded into the breech. Im assuming it was the tight bore. Quite possibly, the 1/4" diameter current of air hitting the ball suddenly. I wish there were a ton of glass barrel tests with a high speed camera.
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#39 Jack Wood

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Posted 12 November 2008 - 06:42 AM

I too am of the opinion that the best starting place is to get the ball safely into the breech, followed by safely into the barrel.

Repeated testing on hand loading v loader loading have proven to me time and time again that the number 1 cause of barrel breaks are loading related.

Hopefully, by the end of the week, we will have more archived glass barrel HSV footage, together with loading data and bolt-to-ball impact data.
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#40 Snipez4664

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Posted 12 November 2008 - 08:34 AM

I too am of the opinion that the best starting place is to get the ball safely into the breech, followed by safely into the barrel.

Repeated testing on hand loading v loader loading have proven to me time and time again that the number 1 cause of barrel breaks are loading related.

Hopefully, by the end of the week, we will have more archived glass barrel HSV footage, together with loading data and bolt-to-ball impact data.


When you hand loaded, was any attention paid to seam orientation?
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#41 cockerpunk

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Posted 12 November 2008 - 10:22 AM

I too am of the opinion that the best starting place is to get the ball safely into the breech, followed by safely into the barrel.

Repeated testing on hand loading v loader loading have proven to me time and time again that the number 1 cause of barrel breaks are loading related.

Hopefully, by the end of the week, we will have more archived glass barrel HSV footage, together with loading data and bolt-to-ball impact data.


this is what simons youtube videos seem to support. and something we saw in the barrel break test.

in simons video is pretty clear the the cause of failure of the ball is because the ball is not concentric with with bore, when the bolt comes forward. this cuases drag on the top of the ball, and eventually deformation. similar in method (but not scope) of the issue we had with emptying the halo every time in our testing, the horrible last couple of paintballs bouncing off the bottom of the breach and comming up to be chopped. both are concentricity issues, of one magnitude or another. this might be a reason why we got the results we got with the barrel break test, because a tighter bore barrel will again, distribute that load better and force concentricity via the taper.



this is clearly not a barrel issue, but a loader problem. one might term that as a "delayed chop" beucase it really is a bolt/ball interaction.

i wonder if a true "barrel break" exists, and if it is something that can be prevented. by this i mean, that a true barrel break (when the paintball arrives in the breach, in tact and perfectly sound and yet still fails when fired) can only be caused by the pneumatic hammer. and again, if we are looking at the loader as the cause for most breaks, there still must be a cause for pump barrel breaks too.

EDIT - damn, just thought of a wicked test idea ....

bryce, do we by any chance have a 0-200ish adjustable reg? anyone else know where we could get something liek that? nm, i found one ...
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#42 Snipez4664

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Posted 12 November 2008 - 10:55 AM

i wonder if a true "barrel break" exists, and if it is something that can be prevented. by this i mean, that a true barrel break (when the paintball arrives in the breach, in tact and perfectly sound and yet still fails when fired) can only be caused by the pneumatic hammer. and again, if we are looking at the loader as the cause for most breaks, there still must be a cause for pump barrel breaks too.

EDIT - damn, just thought of a wicked test idea ....

bryce, do we by any chance have a 0-200ish adjustable reg? anyone else know where we could get something liek that?


Most regs adjust in that range pretty easily - Depending on the flow you need and the mounting an LPR or HPR could probably do the job.
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#43 brycelarson

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Posted 12 November 2008 - 10:57 AM

bryce, do we by any chance have a 0-200ish adjustable reg? anyone else know where we could get something liek that? nm, i found one ...


that's a pretty common reg for welding gasses.

you wanna put a ball in a tapered tube and increase pressure till it pops?

#44 cockerpunk

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Posted 12 November 2008 - 11:00 AM

that's a pretty common reg for welding gasses.

you wanna put a ball in a tapered tube and increase pressure till it pops?


yup, i just messaged the guy making our tapered tube about putting some pipe threads on the wide end so we could do that. on mcmaster i found 5 to 250 psi adjustable regs with gauges for like 22 bucks, might have to pick that up.

alot slower then just squashing them with a machine and a direct acting force, but might help us look at the pneumatic hammer better.
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#45 Snipez4664

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Posted 12 November 2008 - 11:03 AM

:)
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#46 brycelarson

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Posted 12 November 2008 - 11:19 AM

this makes me giggle
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#47 cockerpunk

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Posted 12 November 2008 - 11:21 AM

the trouble with smashing them with air is two fold

1. it will take forever to thread and unthread the setup to get reload the paintball.
2. every time it fails, there will be hell to pay.

so im not saying we are going to switch to that test for the compression test, but i would like to do a couple just to see how it works out for the paintball.
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#48 brycelarson

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Posted 12 November 2008 - 11:27 AM

the trouble with smashing them with air is two fold

1. it will take forever to thread and unthread the setup to get reload the paintball.
2. every time it fails, there will be hell to pay.

so im not saying we are going to switch to that test for the compression test, but i would like to do a couple just to see how it works out for the paintball.



yes, there will be time involved - but I think seeing the pressure differences in even a sample as small as 5 balls may be really, really cool. Just the variance may be small or massive - I have no idea.

The other question would be - do we want to put a dump valve in line to simulate increasing the pressure quickly - or are we just looking at PSI until break?

#49 cockerpunk

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Posted 12 November 2008 - 11:38 AM

without a transducer though, we have no idea what kind of pressure we are putting on the thing if we do something like that.

idk, maybe we dont have the stuff to do that properly.
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#50 brycelarson

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Posted 12 November 2008 - 11:48 AM

without a transducer though, we have no idea what kind of pressure we are putting on the thing if we do something like that.

idk, maybe we dont have the stuff to do that properly.


no, it's simple, you put a reg, then a dump valve then a bleed valve. You open the bleed valve right before the barrel to equalize with outside pressure, then you close that one. You set the reg to the test pressure then open the dump valve - quickly pressurizing behind the ball to the output pressure on the reg. Then you close the dump valve, open the bleed valve to equalize, re-set the reg higher and dump again. repeat until smashy.




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