[cmdrsuds]

Originally Posted by SNAKESNIPER

And is that a tippman? those things aren't the smoothest shooters.

way too quiet to be a tippy, proly a mag
his experiment says over bore cockerpunk says under bore.. but its all really irrelevant if you're not using grade A paint. don't buy a freak kit so you can underbore with s***ty paint.

I use a cocker so my choice is easy as overboring will give me roll outs haha

start with using good paint then look into a new barrel whether it be under or over bore.

[Quacker]

Originally Posted by cmdrsuds

way too quiet to be a tippy, proly a mag
his experiment says over bore cockerpunk says under bore.. but its all really irrelevant if you're not using grade A paint. don't buy a freak kit so you can underbore with s***ty paint.

I use a cocker so my choice is easy as overboring will give me roll outs haha

start with using good paint then look into a new barrel whether it be under or over bore.

Look at the feedneck. Probably a BT-4

[Ninetails]

another thing i noticed in that video. he WAITED till wind died down, then started firing. and for the underbore, he WAITED until the wind came up to fire.

[azhector]

the point where underboring starts to hurt is around .008-.010 under the ball size. i always go around .005 under give or take (i find the first bore it doesnt roll out of, then go another 2 sizes down)

[robertseakykr]

Originally Posted by Ninetails

so i'm confused. you used a .700 bore barrel and a .680 bore barrel? thats a .020 increase, not .006

The paint measured .686 the small-bore barrel was a .680 (.006 under-bored)

Originally Posted by SNAKESNIPER

And is that a tippman? those things aren't the smoothest shooters.

It's a TM-7.

Originally Posted by Quacker

Look at the feedneck. Probably a BT-4

Feedback is relevent to what marker it was because???

I have 10 different markers, that one was easiest to clamp in the gun vice. Btw...it's in a GUN VICE, marker type is irrelevent.

Originally Posted by Ninetails

another thing i noticed in that video. he WAITED till wind died down, then started firing. and for the underbore, he WAITED until the wind came up to fire.

Ok, you got me, you're right, it's all a conspiracy
I don't actually give a **** what you shoot on your marker, unless you're on my team.

Extreme under-boring (>.006") hurts performance. Nobody who's actually shot and recorded tests disputes this. Punkworks included.

This demonstration is EXTREMELY simple to invalidate. All you need to do is take the marker of your choice. Slap on a .680 barrel (or thereabouts). Place a target at 80'. Shoot 25 shots 0f .686+ paint through it and achieve a grouping with 16" or less spread.
Easy-peazy.

[azhector]

no barrel test have been scientific enough to verify one way or another... you need multiple of the same barrels and bore, atleast a case per barrel, make sure its the freshest paint at the highest quality, perfect vice grip, different ranges, include fps difference. so your talking a few hundred bucks to prove one way or another, its not worth it for anyone to log 30 cases of paint into a spread sheet to prove which is better

[robertseakykr]

It actually VERY simple...so simple I'd hazard even a 2k12er such as yourself can do it.
Read my instructions:
1) Take the small bore barrel around .680 of your choice.
2) Put on marker of your choice
3) Set up target @ 80'
4) Clamp marker and shoot 25 shots of .686 or larger paint at target
5) Measure group spread

If you shoot a 25-shot group of paint that's under-bored .006" or larger through your marker at a target that's 80' away and achieve a grouping with 16" or less spread. I'll take my video down and recant everything I've said thus far.

[azhector]

... i know underboring is better, except i just tested back to back bore sizes and didnt range estimate (was same distance both tests) i meant that some people think you can argue overboring to be just as "accurate"

i was talking about punkwork's tests that are in question, nobody has done the test like it should be done, so underboring has yet to be definitively better on paper

[robertseakykr]

You *know* it's better because you did one test, but it can't be shown to be better until somebody does a few thousand tests...ok

The video was posted as a demonstration of what happens when you begin to under-bore to extremes. If you exceed .006" under-bore and you will begin adding very large amounts of spin to the balls. That's why the shot-spread increased in the video. Paintballs are ovoid, not round. The marker isn't particular with what orientation it jams them into the barrel. Because the frictive forces aren't symmetrical around the ball, it will rotate into a lower resistance as it traverses the barrel. This is what adds the spin.

I already know that no one shooting with an extreme under-bore will be able to match the 14" and 16" grouping size at 80' that the large overbore shot in the videos I have on youtube. I've shot and recorded dozens of tests with the same result as the video posted.

That doesn't mean players shouldn't try it, and see for themselves.

[drgonzo]

Originally Posted by SKI008

I think the issue wasn't increased breakage but increased instances of bad spin. It's been a while since I saw the test but I feel like the problem had something to do with the squeeze causing bad spin.

I don't think their results showed "bad" spin at that point. This is a little bit of an issue with citing these tests on internet forums, people tend to look at the numbers as hard limits, but they really are not. A difference of a few thousandths either way is not going to suddenly make your accuracy fall off a cliff, and balls themselves fluctuate a huge amount in size.

[azhector]

robert, do you even remotely understand scientific testing? for something to be 100% definitive for all to accept, it has to be tested with 0 chances of errors. this would require cases of paint shot in an enclosed environment with every possible portion of information written down every shot

[Zippin35]

Originally Posted by azhector

robert, do you even remotely understand scientific testing? for something to be 100% definitive for all to accept, it has to be tested with 0 chances of errors. this would require cases of paint shot in an enclosed environment with every possible portion of information written down every shot

Wow man, what an arrogant statement. Even with extensive testing, based on imperfections of paintballs, peoples incompetence, and general fluctuations of circumstances, it will be a long time until there can "100% definitive for all to accept" type evidence.

For now think of drinking water through a straw. Drinking the last drops that get mixed in with air that makes the gargle sound or whatever gets to the same point as the first sips through a tall, full glass. Both methods get water to your mouth but the latter is much easier to get water. The same holds true with overboring, while overboring, air can escape around the ball. While underboring, little to no air should get around the ball and down the barrel. This means that both will be generally the same "accuracy" but your shots will have more consistency coming through a barrel where all the air input will be behind the ball, as opposed to getting around the ball. Overall, consistency is the largest factor of what paintball players consider accuracy.

[robertseakykr]

Originally Posted by azhector

robert, do you even remotely understand scientific testing? for something to be 100% definitive for all to accept, it has to be tested with 0 chances of errors. this would require cases of paint shot in an enclosed environment with every possible portion of information written down every shot

I have done dozens of tests, recording all relevent information. Here's an example:
http://freepdfhosting.com/751dcb956a.pdf
How many have done and recorded? You also didn't explain how you personally know under-boring is superior.

My instructions to you above are just a VERY simple way to discredit the video I've posted, and certainly aren't meant to give comprehensive conclusions.

If under-boring in excess of .005" has no effect on performance, it will be simple for someone to duplicate the 80' grouping from the overbore with their favorite under-bored barrel.

Originally Posted by Zippin35

... consistency is the largest factor of what paintball players consider accuracy.

Both under-boring and over-boring give similar consistency, but consistency is definitely not the largest factor in paintgun accuracy.

[Zippin35]

Originally Posted by robertseakykr

Both under-boring and over-boring give similar consistency, but consistency is definitely not the largest factor in paintgun accuracy.

I have yet to see that but I am also not claiming to know the definitive answer. Just curious, what do you consider the main aspects of accuracy of a paintball gun/barrel setup?

[SKI008]

Originally Posted by robertseakykr

Both under-boring and over-boring give similar consistency, but consistency is definitely not the largest factor in paintgun accuracy.

I followed you fine until that statement which has left me scratching my head. Explanation please?

Or are you going to say "paintball consistency" is the largest factor in terms of how consistently round each ball is from shot to shot? That makes sense.

[robertseakykr]

Originally Posted by Zippin35

I have yet to see that but I am also not claiming to know the definitive answer. Just curious, what do you consider the main aspects of accuracy of a paintball gun/barrel setup?

Originally Posted by SKI008

I followed you fine until that statement which has left me scratching my head. Explanation please?

Or are you going to say "paintball consistency" is the largest factor in terms of how consistently round each ball is from shot to shot? That makes sense.

Better shot-to-shot velocity consistency would seem intuitively to lead to smaller shot spread...in the vertical axis anyway. In practice though, it actually makes very little difference. Even very good paintballs are rather poor projectiles, and suffer from "random walk" during their flight through the air to the target. This "random walk" is caused by a few factors, the largest being surface imperfections in the paintball (raised seams, dimples etc.) and randomly-oriented imparted spin from the marker/barrel.
Here's a real world example:
http://freepdfhosting.com/8b1a4244d6.pdf
The top list is real I collected during one test. It's a list of 103 recorded shots. You can see this gun delivered a standard deviation in the velocity of 5.12 . That means that 68% of the shots taken were +- 5 fps of the mean velocity of 279 fps. Pretty average consistency I think.
The second list is all the shots that were +-2 fps of the mean velocity of 279fps...so everything between 277fps and 281fps. If velocity consistency were a large factor in shot spread, we should see this group of shots closer together. They're not. They actually look just like the larger group, only fewer. The first group has a vector of 4.7 (vector is the radius of a circle that would encompass 68% of the shots) the second group has a vector of 4.81. Actually it has a slightly worse grouping, but the difference isn't statistically significant.

[SNAKESNIPER (Banned)]

Are there any active variables in play besides the shape of the paintballs themselves?

[Zippin35]

So a few things just looking at your test. Were there any shots +/- 10(ish)? We are looking at the data and simply seeing control group (all shots) vs 1 test group (+/-2). Can you group all the shots in the +/- 10 range? Then we can compare the 2 groups and see if the same still holds true As is we are merely looking at numbers within and compared to the total overall shot, which means that the accuracy, or inaccuracy of the +/-2 group contributes to the way the control group is read. We need to see a second test group, one with a larger velocity spread.

From the looks of your test I would clump all shots from +/-4 in to one group and all shots +/-5 to +/-10 in the second group to see if ball speed exiting the barrel truly affects it as you said. With the current data I can not support it.

[robertseakykr]

Originally Posted by SNAKESNIPER

Are there any active variables in play besides the shape of the paintballs themselves?

Painball roundness may have an effect, but i haven't been able to measure it. I tested several brands of paint a few years ago and the 2 top performers were the roundest balls and the most ovoid balls of the lot. Seams are a huge factor in how paint performs, probably the largest. Induced spins are the next largest factor. I have used sabots to fire zero-spin shots and good paint can achieve a vector of under 3" @ 80'...which rivals First Strike accuracy at the same range.

Originally Posted by Zippin35

So a few things just looking at your test. Were there any shots +/- 10(ish)? We are looking at the data and simply seeing control group (all shots) vs 1 test group (+/-2). Can you group all the shots in the +/- 10 range? Then we can compare the 2 groups and see if the same still holds true As is we are merely looking at numbers within and compared to the total overall shot, which means that the accuracy, or inaccuracy of the +/-2 group contributes to the way the control group is read. We need to see a second test group, one with a larger velocity spread.

From the looks of your test I would clump all shots from +/-4 in to one group and all shots +/-5 to +/-10 in the second group to see if ball speed exiting the barrel truly affects it as you said. With the current data I can not support it.

Here's all the shots with a variance >= 5fps:
http://freepdfhosting.com/81f960382e.pdf

Vector is 4.57 , still no statistically significant difference from the main group.
I'm not saying that good consistency isn't important...only that unless your marker has very poor consistency will it have much effect on shot spread. Good consistency will allow you to chrono closer to the field's limit, which will increase your effective range.

[Zippin35]

Next question is why does the vector include 68% of the shots? I dont know if this is the norm or just a random number, sorry. Secondly how many shots had a deviation >5 and how many <5? There seem to be a lot more in the original group of +/-2. This also leaves a gap from +/-2 to >/= 5. what happened to +/-3 and 4. Sorry if I seem picky but this is the first data I have seen raw like this and it it presented pretty well so I am trying to get everything I can out of it.

Can you give a sequential comparison of <+/-5 to >/= +/-5? and see where that leaves us. Also were you underboring or overbring or what on these test. I understand it is to isolate whether consistency plays a large role, just curious as to what you are shooting through.

[Japy]

So to put aside all this science.. I've had paint roll out of my .679, so I used .677. Not every ball would roll out of the .679, but some would, and I wanted better consistency (and I use a shocker, and efficiency was important at the time- hence underboring). I've also shot paint that sized out for a .682, through my .677 insert without any real impact on paint breakage.

I've concluded the only time that underboring extremes adds to paint breakage is when you're shooting cold, super brittle or deformed paint.

We've got some rentals at my local field that I swear are under a .670 bore and they shoot paint that sizes to .684 without many breaks. Though when that paint swells it tends to get out right stuck in the barrel before breaking.. Lol