Barrel Testing-Tom?

[Wes Janson]

Why is it that (to the best of my knowledge) no one has done any seriously comprehensive testing of a wide variety of barrels before? I've read TK's experiments, but I'd really like to see a scientific, widely-varied test that compares the major barrel systems out there in consistancy, range, breakage, muzzle velocity, and distance velocity (fps@50 meters, for example). Different guns, different paint, different FPS, different temperatures/conditions. A truly comprehensive test that can effectively tell most anyone how their barrel can be expected to perform with any paint when they go out and play. End the petty flame wars and the stupid advertising gimmicks, and put a rest to the issue of what's the best. Why won't someone do this?

[member#10,261]

that would take, like, all day



just kidding
no one has done it because it is just too time consuming.
I wish someone would tho.

**EDIT**I forgot Tom did

[Miscue]

TK has done it.

This sort of data is like what Copernicus came up with. Doesn't matter how he got it, or the truth of it. It kills their "religion" and people don't like that.

[AGD]

Your new here so I will give you a pass. Check out "paintball spin physics" in Deep Blue for all the answers. It's a sensitive issue with me.

AGD

[Aegis]

It is a great question, Wes. However, it might be the wrong question.

The one thing everyone agrees on is the importance of paint to barrel match. That is pretty much the point behind barrel kits.

The problem I have is that I don't believe the manufacturing tolerances for barrels are such that you can assume one .695 bore is the same as another, or any other size. I think you still have to match paint to barrel to make it work.

It can even change during the course of a day. I was shooting some really small Draxxus field paint out of a .684 freak insert, then had to go to a .687 as things warmed up. My son, with a .685 Stiffi, was busting all over the place while my barrel was supposedly smaller. There is now way that I can believe the manufacturers are honing these things down to 1/1000 of an inch and hitting the mark.

I would be very impressed if one batch of freak inserts, marked the same size, matched another batch within a margin of error smaller than the size of the next insert.

[DeeEight]

Why is it whenever someone mentions the 20,000rpm spin being the magic number for spinning a paintball, they never convert that into seconds? Its only 333 revolutions per second people! That is pretty easy to achieve with a rifled barrel.

Has anyone ever bothered to ask Tom if when they did the barrel spinning tests, IF Armson's rifled barrels were available for testing (instead of having to spin a smooth bore barrel).

[GT]

Originally posted by Aegis
The problem I have is that I don't believe the manufacturing tolerances for barrels are such that you can assume one .695 bore is the same as another,

I dont think that is the issue. I believe the tolerence devation is going to be much higher, greater error, with a paintball than a barrel.

Our accuracy problems have more to do with the paintballs than the barrels. Simply put: our balls are not round.

jb

[cledford]

To take what GTRSI said a step further, people miss the forest for the trees. All of my paintball barrels are 100% accurate!!!!! UNTIL THE BALL LEAVES THE BORE! At that point no matter how accurate the barrel was, it NO LONGER HAS ANY IMPACT ON THE BALL. It's not touching it, so how can it have any bearing on how the ball acts? Since all paintballs, no matter how "perfect" (and they are by no means close to the plastic shelled and nylon balls) all of 'em are inherently and fatally flawed due to their shape and weight. They will NEVER be accurate outside a vacuum.

With regard to the spin, read the following, from http://www.automags.org/resource/tec...pinning.shtml:

The problem is the liquid fill, when you rotate the shell, the liquid tends to stay where it is. The best example of this is a glass of water with ice floating in it, when you rotate the glass the ice stays in the same place (you have all seen it). So if you can grab the ball hard enough to go from 0 to about 10,000 RPM's in 5 thousands of a second (remember TechTip #1?) Yes the shell is spinning but the fill is not. When the ball leaves the barrel the viscosity of the fill slows the shell down but the fill's rotation is speeding up from the shell too, so you get an almost instant reduction of the RPM's out of the barrel. The balls rotation does not come to a complete stop because the shell does impart some spin to the fill. In order to test this properly we actually developed a gun that spun the barrel, with the ball in it, up to 30,000 RPM's and then shot the ball out.

When someone has taken the time to build something that spins a paintball 30,000rpm and the ball still, almost immediately, stops spinning upon exiting the bore, do you really need to test the hammer-head or the armson?

Miscue's quote hit the nail on the head - I'm putting it into my sig...

-Calvin

[DeeEight]

Originally posted by cledford
When someone has taken the time to build something that spins a paintball 30,000rpm and the ball still, almost immediately, stops spinning upon exiting the bore, do you really need to test the hammer-head or the armson?.

-Calvin [/B]

Yes, when a rifled barrel put 3 to 4 times the spin on the ball (while moving down the barrel) that actually spinning the barrel and breech at 30,000 rpms did before firing.

See, rifling is rated by its twist ratio, which is usually how many times the projectile will rotate in the barrel. So a 1 in 6 twist is 6 rotations of the projectile. Well if the barrel is a foot long, that's 6 rotations per foot travelled, so if it then travels 280 feet in one second, that's 1,680 rotations in a second. Multiply that by 60 to get rpm and you get 100,800 rpm.

Use a 1 in 9 twist though and its 50% more. 1 in 9 twists are fairly common in rifles.

[Mike Smith]

Y'all are making my head hurt.....

Here's how I tested my Hammerhead Barrel:

I shot it, noting how easy it was to hit a 2" tree branch about 60 feet away.

I traded barrels and shot my Dye and my Lapco. There was no comparison. The Hammerhead was WAY more accurate than either of my other barrels. Of course, I forgot to try out my original Mag barrel with the triangle openings, but it was not as good as my Dye, the last time I used it.

FYI, cronoed about 270, and used some left-over scenario paint.
Hammerhead = 14"
Lapco = 12"
Dye = 10"

[cledford]

Originally posted by DeeEight


Use a 1 in 9 twist though and its 50% more. 1 in 9 twists are fairly common in rifles.

OK, I'll play your silly game, how many twists per inch does the hammer-head have? Where is the high speed digital photography that SHOWS that the same thing that STOPS a ball from spinning at 30,000rpm (stationary viscous fill exerting friction against spinning shell) doesn't affect a ball spun faster? Explain *EXACTLY* how even spinning a ball at any number of RPM along a horizontal axis does ANYTHING to change the vortices, turbulence and *cavitation* *behind* the ball which cause it to bounce around in the air? Please DO NOT make any references to firearms ballistics in your explanation. Discussing a CONICAL projectile, many times denser then the medium that it is being propelled through, with virtually zero cross section at the nose is in no way related.

You need to read the thread in Deep Blue. The problem with paintball accuracy is as follows, due to the aerodynamic properties of the projectile (a sphere with a large circumference) the ball "pushes" air out of it's path during travel. The cause an area of low pressure behind the ball (like the one under an aircraft wing) the "caves in" in a random fashion. This randomness bounces the ball around in the air. Spinning the ball horizontally does change what happens when you shove a ball quickly through the atmosphere. Next time you are in a pool try pushing your hand (held flat) through the water rapidly. you will feel hand moved around against your will no matter how hard you try to keep on a straight path. No imagine your hand moving on its own, and spinning along an axis parallel with the direction of travel. Do you expect that it would STOP fluttered around due to the spin? No likely. The same cross section, displacing the same amount of fluid, at the same rate, causing the same area of "cavitation" behind it would be occurring.

As an aside on firearm twist rate - did you know that for some bullets twist rates that exceed a certain speed can cause the projectiles to literally to fly/fling apart? For extra credit, what do you think would happen to a paint ball assuming it was (could be) spun at a similar rate?

-Calvin

[dmocratic]

Originally posted by DeeEight
Yes, when a rifled barrel put 3 to 4 times the spin on the ball (while moving down the barrel) that actually spinning the barrel and breech at 30,000 rpms did before firing.

See, rifling is rated by its twist ratio, which is usually how many times the projectile will rotate in the barrel.

No. Rifling is rated by the number of inches of barrel length in which on twist occurs.

So a 1 in 6 twist is 6 rotations of the projectile.

No, a 1 in 6 twist means that for every 6" the paintball travels forward, it will rotate once.

[...] so if it then travels 280 feet in one second, that's 1,680 rotations in a second. Multiply that by 60 to get rpm and you get 100,800 rpm.

No, in a 1 in 6" twist barrel, a 280 fps projectile will be rotating at 280*12/6 = 560 rps, or about 33,600 rpm, which not suprisingly is the rotation rate Tom used in his tests.

Use a 1 in 9 twist though and its 50% more. 1 in 9 twists are fairly common in rifles.

A 1 in 9" twist spins a bullet _less_ than a 1 in 6 twist.

[SlartyBartFast]

Spinning paintballs. What a laugh.

The whole pathetic debate is identical to my battles against the hoards of SP followers back in the early 90's extolling the virues of spiral ports imparting spin on the ball and performing the miraculous act of releiving vaccum behind and pressure in front.

Catch a ball shot from a hammerhead without breaknig it. Unless there are nice deep, well defined, grooves on only one axis, there's no way that sucker is putting any spin what-so ever on the ball.

And if you're going to get into the silly habit of quoting real firearm ballistics (which don't apply to paintball one whit) at least look to similar weaponry. Don't think I ever saw rifling in cannons or muskets.

And that's before the fact that TK already proved them wrong but the drones, I'm sorry, druids still believe in fauries.

TK spun the ball before firing. Ensuring the fill and shell were both spinning.

Even if a barrel could spin a ball along the axis of the barrel (and I challenge anyone to prove any barrel can), there's no way the shell and fill are spinning at the same rate as per TKs tests.

[DeeEight]

Originally posted by cledford

OK, I'll play your silly game, how many twists per inch does the hammer-head have? Where is the high speed digital photography that SHOWS that the same thing that STOPS a ball from spinning at 30,000rpm (stationary viscous fill exerting friction against spinning shell) doesn't affect a ball spun faster?

Actually where's the high speed photography of any sort that proves the viscous fluid stops or even slows the balls from spinning at all?

Be nice if the "well tom proved it" folks could provide the actual evidence of the proof, not simply quoting what TK said on the subject a decade ago.

Especially since if the fluid actually stopped the spin instantly, then flatline barrels wouldn't work at all, because the backspin would be arrested just the same was that TK claimed that sidespin was arrested. So which is it boys?

[cledford]

I just checked Deep Blue, thought they'd been posted - but a couple of links are busted - so I'll see what I can come up with. In the mean time, I'll relax my request to something along the lines of "where are the *claims* of high speed digital photography (or other scientific or actual testing) that indicate that spin applied by the hammerhead continues (or is even present) after the ball leaves the muzzle?" I'd assume that any company worth their salt enough to come out with such a revolutionary product, one that cheats the laws of physics, would have data beyond "we shot a tree and our groups were smaller" to back up such a huge step forward in PB technology.

On to a couple of other issues. Number one, bad point about the flatline. First, it has nothing to do with your assertions. Paintballs are inaccurate due to the previously mentioned area of low pressure and the dynamics of what happens in that area during flight. The flatline spin does nothing (AFIK) to mitigate that area of low pressure *behind* the ball - so it is no more accurate then a typical PB. The spin (which is actually imparted) also creates an area of LP/lift below the ball which alters is flight path on a vertical axis only. The flatline puts a hell of a lot of spin on the ball (I think remember ~200,000rpm) which is a far cry from what rifled barrels could do, IF they did work - which we know isn't the case. Even if the rifling did work (put spin on the ball) it still doesn't mitigate the CORE reason paintballs are inaccurate - the area of LP (and insuring turbulence) behind the ball - so what's your point? Actually you addressed nothing brought up in the last few posts other then to attack Tom for suggesting that he may have fabricated data, which you do on behalf of people who don't even seem to go that far. The only thing your post caused me to reconsider is my assumption that too much spin would cause a PB to fling apart - because as you stated the Flatline works.

OK, so we're standing by for real argument. It doesn't take Tom Kay's word that a spheres path when shoved quickly through a fluid does a "random walk", there are a number of links to non-PB related sights and even formulas that deal with just that issue. So back on track, how does the dubious amount (if any) of horizontal axis spin put on a ball change the behavior of fluid dynamics? I'd suggest asking the people who sell you the barrel - since they're such rocket scientists maybe they could explain how it works - if fact I invite their comments.

-Calvin