[LJK]

Greetings everyone: I don't know if its just my imagination but my pump gun shooting evil seems more accurate at 250 fps than at 275 to 300 fps? I was wondering if the imperfections in the paintballs are magnified at higher velicities causing accuracy to deteriorate? I know I'm giving up some range at 250 fps, but accuracy under 100 ft really seems consistantly better. Has anyone found this to be true?

[UV Halo]

In airguns, that use non-round projectiles, an increase in accuracy at higher velocities is directly attributed to a reduction in the amount of time, the projectile is subjected to while on it's way to the target.

With paintballs, this could also be true however, paintball imperfections and vortex shedding conspire to reduce this benefit, if there is one at all.

I would check the first part of your post:

Is it just your imagination? If you have access to an indoor range with a distance of let's say 75ft, 50 paintballs, a wipeable target board with a grid, a chronograph, a gun, and a means of clamping it to a bench/table.

Experience has taught us that our vision is the least reliable source of information for this sort of thing.

[cockerpunk]

i can tell you it doesn't ... but don't believe me because i don't have the data (i did at one point though).

you should test it yourself!

[Kjimenez]

I know that there's some anecdotal evidence for this in older paintball publications -- I know Bud Orr mentioned speeds in an interview in the "Complete Guide to Paintball". Something about the design of the Sniper, and how the marker wouldn't fire past a certain pressure, which he equated to something around 350 FPS. He followed that by saying "Not that the 'gun shot well at that speed". I recall old articles in Paintball and APG recommending chronographing around 275-285, saying that higher speeds were detrimental to accuracy.

I've noticed this issue myself but not at the speeds you describe -- for me, it's had to be pretty well above 300.


So whether you're correct or not, other people have experienced the same thing.

One thing I wanted to bring up -- we always talk about where the ball lands, but less about how it flies through the air. This is an issue. When only measuring point of impact, a ball that curves five feet right, up a foot, down a foot, and five feet left has the same impact on our measurements as one that does not deviate from the predicted path at all, though the first situation is very undesirable.

Is there a way we could use high speed video to look at the entire flight path of a paintball, at different velocities, and see if there are any trends?

[UV Halo]

Kjimenez, on 20 August 2012 - 03:11 PM, said:

I know that there's some anecdotal evidence for this in older paintball publications -- I know Bud Orr mentioned speeds in an interview in the "Complete Guide to Paintball". Something about the design of the Sniper, and how the marker wouldn't fire past a certain pressure, which he equated to something around 350 FPS. He followed that by saying "Not that the 'gun shot well at that speed". I recall old articles in Paintball and APG recommending chronographing around 275-285, saying that higher speeds were detrimental to accuracy.

I've noticed this issue myself but not at the speeds you describe -- for me, it's had to be pretty well above 300.


So whether you're correct or not, other people have experienced the same thing.

One thing I wanted to bring up -- we always talk about where the ball lands, but less about how it flies through the air. This is an issue. When only measuring point of impact, a ball that curves five feet right, up a foot, down a foot, and five feet left has the same impact on our measurements as one that does not deviate from the predicted path at all, though the first situation is very undesirable.

Is there a way we could use high speed video to look at the entire flight path of a paintball, at different velocities, and see if there are any trends?

Here's a problem I have with most historical data, provided by experienced players. They were doing the same sorts of assessments that most people do today- shoot it, and let our visual systems tell us how close the paintball got to our non-specific point of aim (i.e. down the barrel). Tom Kaye (TK) is a notable exception in that he tested a ton of ideas with good rigor and good documentation, and his early work busted a butt-load of myths that were all derived from 'personal observations' of 'experienced players'.

High Speed Photography has been employed by TK to capture the flight of a paintball, and it has shown that the paintball moves about the axis defined by the barrel bore. That being said, what practical information would be gained by conducting such testing and analysis? Especially, given ball-drop (due to gravity) aside, the behavior appears to be random.

[Kjimenez]

UV Halo, on 20 August 2012 - 03:41 PM, said:

Kjimenez, on 20 August 2012 - 03:11 PM, said:

I know that there's some anecdotal evidence for this in older paintball publications -- I know Bud Orr mentioned speeds in an interview in the "Complete Guide to Paintball". Something about the design of the Sniper, and how the marker wouldn't fire past a certain pressure, which he equated to something around 350 FPS. He followed that by saying "Not that the 'gun shot well at that speed". I recall old articles in Paintball and APG recommending chronographing around 275-285, saying that higher speeds were detrimental to accuracy.

I've noticed this issue myself but not at the speeds you describe -- for me, it's had to be pretty well above 300.


So whether you're correct or not, other people have experienced the same thing.

One thing I wanted to bring up -- we always talk about where the ball lands, but less about how it flies through the air. This is an issue. When only measuring point of impact, a ball that curves five feet right, up a foot, down a foot, and five feet left has the same impact on our measurements as one that does not deviate from the predicted path at all, though the first situation is very undesirable.

Is there a way we could use high speed video to look at the entire flight path of a paintball, at different velocities, and see if there are any trends?

Here's a problem I have with most historical data, provided by experienced players. They were doing the same sorts of assessments that most people do today- shoot it, and let our visual systems tell us how close the paintball got to our non-specific point of aim (i.e. down the barrel). Tom Kaye (TK) is a notable exception in that he tested a ton of ideas with good rigor and good documentation, and his early work busted a butt-load of myths that were all derived from 'personal observations' of 'experienced players'.

High Speed Photography has been employed by TK to capture the flight of a paintball, and it has shown that the paintball moves about the axis defined by the barrel bore. That being said, what practical information would be gained by conducting such testing and analysis? Especially, given ball-drop (due to gravity) aside, the behavior appears to be random.

The first part of my post is just to let the OP know that yes, other people have observed what he believes he is experiencing.

I know that the behavior is random, but I am wondering if velocity effects the frequency or magnitude of the random, drifting behavior. (Vortex shedding is what I am attempting to refer to, I think).

This basically helps us know if higher velocity means an increased likelihood of the ball veering off and hitting a twig or bush rather than the target. That would also be another argument to use against the misguided people that turn their velocity up all the way to shoot further.

[UV Halo]

Kjimenez, on 20 August 2012 - 05:41 PM, said:

The first part of my post is just to let the OP know that yes, other people have observed what he believes he is experiencing.

I know that the behavior is random, but I am wondering if velocity effects the frequency or magnitude of the random, drifting behavior. (Vortex shedding is what I am attempting to refer to, I think).

This basically helps us know if higher velocity means an increased likelihood of the ball veering off and hitting a twig or bush rather than the target. That would also be another argument to use against the misguided people that turn their velocity up all the way to shoot further.

Well, you certainly bring up interesting points that would address 'how likely is my shot going to be intercepted by a nearby bush / twig / tree while on it's way to the target?'.

TK's method might not answer this satisfactorily due to the limited number of cameras that could be used to capture the entire trajectory. One possibly cool way would be to put an HSV camera beyond a rock solid, optically transparent pane and shoot towards a camera that is inline with the bore of the gun. However, Given the arc of a paintball, I don't think it would be feasible to try and capture the entire flight. So, it may just be something like 50ft. It would certainly make for some good video

[Kjimenez]

UV Halo, on 21 August 2012 - 10:13 AM, said:

Kjimenez, on 20 August 2012 - 05:41 PM, said:

The first part of my post is just to let the OP know that yes, other people have observed what he believes he is experiencing.

I know that the behavior is random, but I am wondering if velocity effects the frequency or magnitude of the random, drifting behavior. (Vortex shedding is what I am attempting to refer to, I think).

This basically helps us know if higher velocity means an increased likelihood of the ball veering off and hitting a twig or bush rather than the target. That would also be another argument to use against the misguided people that turn their velocity up all the way to shoot further.

Well, you certainly bring up interesting points that would address 'how likely is my shot going to be intercepted by a nearby bush / twig / tree while on it's way to the target?'.

TK's method might not answer this satisfactorily due to the limited number of cameras that could be used to capture the entire trajectory. One possibly cool way would be to put an HSV camera beyond a rock solid, optically transparent pane and shoot towards a camera that is inline with the bore of the gun. However, Given the arc of a paintball, I don't think it would be feasible to try and capture the entire flight. So, it may just be something like 50ft. It would certainly make for some good video

I really don't see a need for the attitude.

If you're being serious, I think the ideal rig would have cameras set up along the entire flight path, to measure variation vertically and horizontally.

[LJK]

As I understand it velocity is a big part of the vortex shedding equation. So theoretically a change in velocity would make a difference in the flight of the greatly flawed paintball, but at the rather slow speeds of paintball plus or minus 50 fps wouldn't make a noticeable difference? Is this correct?

[Troy]

LJK, on 21 August 2012 - 12:30 PM, said:

As I understand it velocity is a big part of the vortex shedding equation. So theoretically a change in velocity would make a difference in the flight of the greatly flawed paintball, but at the rather slow speeds of paintball plus or minus 50 fps wouldn't make a noticeable difference? Is this correct?

I don't know if this is true.

[UV Halo]

Kjimenez, on 21 August 2012 - 11:50 AM, said:

I really don't see a need for the attitude.

If you're being serious, I think the ideal rig would have cameras set up along the entire flight path, to measure variation vertically and horizontally.

I was serious- note the lack of a emoticon of any sort in the first part of my response.

Yeah, I agree- Ideally, you would have cameras along the entire path but, given the extremely low number of HSV cameras in this community (Punkworks' is the only one I've seen), I don't see that happening any time soon. You don't even need two cameras to capture the vertical and horizontal placement. If I remember correctly, through clever positioning of a couple mirrors in front of each camera, with the paintball flying between them and the camera, you could capture the vertical and lateral displacement with each frame.

[Kjimenez]

UV Halo, on 21 August 2012 - 03:32 PM, said:

Kjimenez, on 21 August 2012 - 11:50 AM, said:

I really don't see a need for the attitude.

If you're being serious, I think the ideal rig would have cameras set up along the entire flight path, to measure variation vertically and horizontally.

I was serious- note the lack of a emoticon of any sort in the first part of my response.

Yeah, I agree- Ideally, you would have cameras along the entire path but, given the extremely low number of HSV cameras in this community (Punkworks' is the only one I've seen), I don't see that happening any time soon. You don't even need two cameras to capture the vertical and horizontal placement. If I remember correctly, through clever positioning of a couple mirrors in front of each camera, with the paintball flying between them and the camera, you could capture the vertical and lateral displacement with each frame.

Okay, sorry. Inflection and the Internet don't mix.

Let's see... what about this. Stick some posts in the ground, painted with stripes for measurement purposes, with a beam across the top painted the same way. Set these up along the flight path of the ball. Mount the camera along the axis of the barrel, so it can capture the whole flight. Approximate measurements can be taken using the posts. Would that work?

WAIT, better idea. A still photo with a locked-open shutter. Creates a "tracer" effect. Two cameras should give all the data you need, and if you shoot past a checkerboard type background you can take measurements.

This post has been edited by Kjimenez: 21 August 2012 - 08:15 PM

[Troy]

Kjimenez, on 21 August 2012 - 08:10 PM, said:

UV Halo, on 21 August 2012 - 03:32 PM, said:

Kjimenez, on 21 August 2012 - 11:50 AM, said:

I really don't see a need for the attitude.

If you're being serious, I think the ideal rig would have cameras set up along the entire flight path, to measure variation vertically and horizontally.

I was serious- note the lack of a emoticon of any sort in the first part of my response.

Yeah, I agree- Ideally, you would have cameras along the entire path but, given the extremely low number of HSV cameras in this community (Punkworks' is the only one I've seen), I don't see that happening any time soon. You don't even need two cameras to capture the vertical and horizontal placement. If I remember correctly, through clever positioning of a couple mirrors in front of each camera, with the paintball flying between them and the camera, you could capture the vertical and lateral displacement with each frame.

Okay, sorry. Inflection and the Internet don't mix.

Let's see... what about this. Stick some posts in the ground, painted with stripes for measurement purposes, with a beam across the top painted the same way. Set these up along the flight path of the ball. Mount the camera along the axis of the barrel, so it can capture the whole flight. Approximate measurements can be taken using the posts. Would that work?

WAIT, better idea. A still photo with a locked-open shutter. Creates a "tracer" effect. Two cameras should give all the data you need, and if you shoot past a checkerboard type background you can take measurements.

I really like the idea of an open shutter.

EVEN BETTER IDEA... they still make glow in the dark paintballs right? If not, paint reballs with glow in the dark material. You could, even make a grid with glow in the dark (or UV active) paint as well. Ultimately, I think you can get a better, clearer, picture with that kind of method.

It would be REALLY cool to see a marker shooting a glow in the dark ball (obviously in a dark room) with a laser site mounted to the barrel and a little fog in the air so you can see the laser beam... How cool would that be?

[Kjimenez]

Troy, on 21 August 2012 - 08:44 PM, said:

Kjimenez, on 21 August 2012 - 08:10 PM, said:

UV Halo, on 21 August 2012 - 03:32 PM, said:

Kjimenez, on 21 August 2012 - 11:50 AM, said:

I really don't see a need for the attitude.

If you're being serious, I think the ideal rig would have cameras set up along the entire flight path, to measure variation vertically and horizontally.

I was serious- note the lack of a emoticon of any sort in the first part of my response.

Yeah, I agree- Ideally, you would have cameras along the entire path but, given the extremely low number of HSV cameras in this community (Punkworks' is the only one I've seen), I don't see that happening any time soon. You don't even need two cameras to capture the vertical and horizontal placement. If I remember correctly, through clever positioning of a couple mirrors in front of each camera, with the paintball flying between them and the camera, you could capture the vertical and lateral displacement with each frame.

Okay, sorry. Inflection and the Internet don't mix.

Let's see... what about this. Stick some posts in the ground, painted with stripes for measurement purposes, with a beam across the top painted the same way. Set these up along the flight path of the ball. Mount the camera along the axis of the barrel, so it can capture the whole flight. Approximate measurements can be taken using the posts. Would that work?

WAIT, better idea. A still photo with a locked-open shutter. Creates a "tracer" effect. Two cameras should give all the data you need, and if you shoot past a checkerboard type background you can take measurements.

I really like the idea of an open shutter.

EVEN BETTER IDEA... they still make glow in the dark paintballs right? If not, paint reballs with glow in the dark material. You could, even make a grid with glow in the dark (or UV active) paint as well. Ultimately, I think you can get a better, clearer, picture with that kind of method.

It would be REALLY cool to see a marker shooting a glow in the dark ball (obviously in a dark room) with a laser site mounted to the barrel and a little fog in the air so you can see the laser beam... How cool would that be?

Ridiculously cool, imho.

[UV Halo]

For an ideal setup, the laser, open shutter, and UV round would be very cool and provide good information. However, think about how far back the camera would have to be to capture the entire trajectory, relative to the amount of light given off by the UV round. What kind of camera requirements do we have here, and how common would such a camera be?

When I think about it, my inline HSV camera idea would present some other challenges- scale. From the camera's perspective, objects near the muzzle would appear to move less than objects near the camera, assuming they moved the same amount.

[Troy]

Even if we need a couple cameras, finding a couple that are capable of doing an open shutter is a much lower bar to cross then finding a couple high speed video cameras.

[UV Halo]

Troy, on 22 August 2012 - 10:17 PM, said:

Even if we need a couple cameras, finding a couple that are capable of doing an open shutter is a much lower bar to cross then finding a couple high speed video cameras.

I agree. TK's approach was much the same but, for a shorter distance, and he used a strobe to provide lighting.

[cockerpunk]

the problem we have with our high speed camera is that its not good enough resolution at fast enough, and it doesn't have a near infinite depth of focus, which is what you would need to look down the flight path of the ball. have a hard enough time getting 10-12 feet of focus out of it at 1200 fps.

but, if you arnt looking at spin, you dont need a picture of the ball. so you just put up thin paper at 10 foot intervals, and shoot through that to measure ball position.

on the main topic of the thread you don't even need that though, should just be a simple accuracy test.

[Blade of grass]

UV Halo, on 21 August 2012 - 03:32 PM, said:

Kjimenez, on 21 August 2012 - 11:50 AM, said:

I really don't see a need for the attitude.

If you're being serious, I think the ideal rig would have cameras set up along the entire flight path, to measure variation vertically and horizontally.

I was serious- note the lack of a emoticon of any sort in the first part of my response.

Yeah, I agree- Ideally, you would have cameras along the entire path but, given the extremely low number of HSV cameras in this community (Punkworks' is the only one I've seen), I don't see that happening any time soon. You don't even need two cameras to capture the vertical and horizontal placement. If I remember correctly, through clever positioning of a couple mirrors in front of each camera, with the paintball flying between them and the camera, you could capture the vertical and lateral displacement with each frame.

Or get a wide angle lens.