What Barrel is This?

[ghost flanker]

Actually, these have some merit, unlike the spiral rifling we've seen in the past. I'd actually like to see a real controlled test on these barrels. It would be interesting to see the results.

Well then you're in luck

http://www.youtube.com/watch?v=197yZ859h74

[athomas]

Good information, and agrees with most of the data I've seen. No actual test results though.

His statement on the barrel length only making a 7% difference because the change in velocity is only a 7% change is incorrect. A 7% change in velocity due to barrel length could result in a drastic change in efficiency. The scale of barrel length to efficiency is not linear. It takes a lot more air to change the velocity at the top of the scale than it does at the bottom of the scale. Each 1 fps increase requires more air than the previous 1 fps increase.

[ghost flanker]

I was just giving you the short answer there but there's a whole slew of footage on their website documenting their different tests and results. Data spreadsheets included. If you can't find what you're looking for, just PM Cockerpunk here on AO. I'm sure he'd be happy to tell you anything you wanted to know about their tests.

http://www.punkworkspaintball.com/index.php?p=2

By the way, what data were you referring to that you've seen? I'd be interested in checking that out, as well.

[cockerpunk]

Well then you're in luck

http://www.youtube.com/watch?v=197yZ859h74

only thing id add, and ill talk to bryce about adding that now as a caption/footnote. is when we shot that video and did all of our testing, the absolute largest paint around was ~.685. the smallest we were seeing was sub .679 blow test.

so when he says, .679 on everything, he is talking about at most an underbore of .006" and in most cases an underbore even less than that (.003"). we also did the insanity underbore test, and found that around .010" is when underboring really did start breaking paint on a regular basis.

i wish instead of talking about bore sizes folks just used difference from blow test, as that is really what matters, but folks don't.

[SummaryJudgement]

I would like to throw this out there in case anyone has seen similar results.

I knew a handful of guys that all used the Armson rifled barrels on their Micromags (1997). When they would get a ball break and paint was in the breach/barrel, the paintballs would do the weirdest looking stuff. They would actually travel forward, but in a spiral/corkscrew kind of path. Like rotating about a straight axis in a forward motion. Totally strange to see (it happened because of the side-spin on the ball and forward force). It looked totally unnatural.

Anyone else ever see this? It never happened with the Straight-shots, I don't know if you'd consider the length-wise grooves "rifling" necessarily.

Just curious

[athomas]

...They would actually travel forward, but in a spiral/corkscrew kind of path. ...

Anyone else ever see this? It never happened with the Straight-shots, I don't know if you'd consider the length-wise grooves "rifling" necessarily.

Yeah, I've seen that before, but with normal barrels. It is a "knuckle-ball" effect. I suspect it has to do with the paint on the ball causing the ball to be off balance. Normally this wouldn't be an issue because the ball is symetrical without any major surface protrusions that would allow the air to affect the flight. Once you introduce paint onto the shell, the air has something to act on.

Rifling is a spiral groove to induce a controlled spin. I consider the lengthwise grooves as just what they are, lengthwise grooves.

... we also did the insanity underbore test, and found that around .010" is when underboring really did start breaking paint on a regular basis.

i wish instead of talking about bore sizes folks just used difference from blow test, as that is really what matters, but folks don't.

Yes, its the relationship with the paint that matters, not the absolute size.

[athomas]

By the way, what data were you referring to that you've seen? I'd be interested in checking that out, as well.

The data I am refering to is nothing that I can show you. They are test values that I have seen over the past 25+ years of playing paintball. As such, from a scientific approach I can only offer an opinion and a reasonable argument as to the theory behind any observations, since I can't produce the real data.

Quite often, guys around here, like Cockerpunk or some others, post some real test data and very often, the real data agrees with the values I have seen over the years. That is the beauty of real testing and not just holding a gun and firing some shots. Physics doesn't change. The same values that were generated for a paintball gun 25 years ago, still hold true today.