Paintball

[brycelarson]

Originally Posted by pump

everybody, guess what i got

herpes?

[pump]

incorrect, but ill test for AIDS to determine if i herpes or not, that is your style isnt it?

[brycelarson]

Originally Posted by pump

everybody, guess what i got

what did you get man?

I'm not sure if the above was a gay joke - but yes, I am very thorough - I suggest testing for all kinds of stuff if you're not sure about something....

[HP_Lovecraft]

Originally Posted by drg

Well you are right that HP's discussions don't seem to consider the flatline phenomenon as the source of the spin,

He does make an interesting point that I never considered- In that the CooperT does not spin directly, but forces it against the barrel.

My barrel test seems to work against that theory, though in MY case, my barrel was not overbored enough. Even if the theory above was correct, that particular barrel would have contacted the ball on all sides. So it may not specifically disprove it, though on my opinion, it might.

I think the problem is that for most players, there first and only experience with legitimate backspin systems is the Flatline, and Apex. So, it might appear that the only method to backspin the paintball would be via the barrel.

So for other systems that work (ie CooperT, GalaticZ), that does not seem to fit the model. The GalaticZ, for example, uses the "HopUp" system common on airsoft guns, with a rubber skid plate on the upperbreech.

Both the HopUp Airsoft, and GalatacZ systems have also been shown to produce the effect.

That said, all the different systems (ie Flatline, CooperT, GalaticZ) need an overbored. For CooperT/GalaticZ, you can match the barrel to the paint. For the Flatline, you have to match the paint to the barrel (ie RP Marb), which is very limiting if you play at FPO fields.

The Apex is neat in that its the only system that can use any ID barrel, since it spins it AFTER. Also, since the Apex is not needed to accellerate the ball, it is far more overbored then the flatline, allowing for any kind of paint to be used.

[agentSmith]

John Satclaire,


Automags.org-Deep Blue

The Dimpled paintball is beaten to death in sticky #2, the first one pertains to our current discussion.

Wycked54,

If im not mistaken it appears that the cooper t bolt would force the ball upwards when the air hits the ball causing the ball to roll against the top of the barrel. Since the barrel is almost smooth than there would be only small groves and rough patches along the way in various direction there by causing corkscrews due to the randomness of the friction.

In my own long experience with this bolt, in guns with barrels of different lengths(I've had PGP and P68SC versions) I'd say that it CAN roll against the sidewall but that's worst case.
I think it is forced against the top only in the first instant and an elastic effect snaps the paintball like a rubberband(explaining why there's more barrel breaks with these babies).
An overbored superpolished barrel is by far the best thing to put around one of these bolts. It seems from my study(believe me I was interested in where every one of those cases and cases and cases of balls I fired went) that it works best if the barrel is so smooth that the ball can 'peel out', in other words gain alot of spin in the first instant. This implies that more spin than the 'rolling with traction' method is put on by the backspin bolt and probably by the first 'bounce against the curve' in a flatline. I can watch the spin on my P68SC slowly diminish as the barrel gets dirtier throughout the day.

EDIT: A question worthy of study is whether this lessening of spin is from 'traction' against a single wall or the tightening of the bore in general due to accumulation of goo. Palmer's Glass Barrel could answer that question for us.

Rob

[John Satclaire]

Originally Posted by brycelarson

what did you get man?

I'm not sure if the above was a gay joke - but yes, I am very thorough - I suggest testing for all kinds of stuff if you're not sure about something....

Although his post was less than clearly written, it seems pretty transparent that "doing a test for AIDS to see if one has Herpes" is a commentary on your approach to determining whether backspin bolts create a flatline effect.

Or something.

[brycelarson]

Originally Posted by John Satclaire

Although his post was less than clearly written, it seems pretty transparent that "doing a test for AIDS to see if one has Herpes" is a commentary on your approach to determining whether backspin bolts create a flatline effect.

Or something.

Yeah, I know. Sometimes misunderstanding is the best defense....

agentSmith - Thanks for the report on your experience with the backspin bolts. I think other than HP you're the first that has offered personal experience. Based on shooting a bunch of paint with these guys - how great is the expected range increase that you get? Is it on the order of magnitude of the flatline - or more subtle?

[HP_Lovecraft]

On a similar idea, I've wondered if it would work if someone would take a TIGHTbore barrel, and cut off the bottom half of the barrel. That way, the friction for the tightbore barrel only hits the top, and without the bottom to couteract, it produces the spin.

In effect, do the same thing as the Tippmann, without the need for a large, proprietary, absurd shaped barrel...

If you do a patent search, there is actually a bunch of different backspin ideas that have been patented, but never used. Probobly a case of "works in theory, but not in practice".

A good example: Anyone remember the Bob Long Longshot barrel? Not the recent one, but the one from the early 90s? It had a bunch of holes drilled into the bottom, on a variation of my idea above. He claimed it produced a backspin, and extended range, but cleary it was just hype.

For that matter, a common mod in the early 90s was an "ANGLE CUT" at the end of the barrel. Sorta like those odd AK-74 flash-hiders. The hype was that it also made the backspin by giving it a quick "spin" just before it left. Again, just hype.

So, even though I was hard on the original poster, I agree that most systems are fakes. Pretty much everything in paintball is.

[Fubarius]

Originally Posted by HP_Lovecraft

A good example: Anyone remember the Bob Long Longshot barrel? Not the recent one, but the one from the early 90s? It had a bunch of holes drilled into the bottom, on a variation of my idea above. He claimed it produced a backspin, and extended range, but cleary it was just hype.

I always thought that putting the holes on the top of the barrel would work better for getting a back spin. The sudden reduction of air pressure on that side of the barrel, combined with increased friction (porting being a bit more bumpy than smooth metal) could theoretically lift the ball up and give it a back spin.

[cockerpunk]

the only trouble with the "push up against the top of the barrel theory" is this -

any flow around the bottom of the ball, will cause a pressure drop, which intern will cause the net force on the ball to be downward, back into the center of the barrel.

unless the mass flow rate of the air is great enough to impart a force due to its mass, the force cuased by air under the ball will acutally pull the ball down into the center of the ball.

shooting from the hip, im doubting the mass flow rate is great enough.