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[syk0weasel]

Cooper-T Bolts

Theres the cooper-t undershot bolts. I also remember the Micromag Galactic systems Z body that had an adjustable pad that caused the ball to have backspin. It also needed a large bore barrel to work correctly.

[HP_Lovecraft]

I don't think CooperT has anything left. A few people here have said that he stopped making new items years ago, and has been selling everything off.

I have more experience with backspin bolts that probobly anybody. I've used them in VMs, Cockers, Sterlings, Snipers, (all CooperTs) and recently my rainmaker and Montneels.

On the VM, the bolt looks like this:


Basically, it was a SOLID piece of delrin, with a groove cut into the bottom, like this:


Like you said, it diverts the blast from the bolt at the base of the paintball, to give it a backspin, producing the "Magnus Effect" found on the later Flatline.

VERY easy to make one for any stacked tube gun. Nothing to modify on the gun, so if yo have an extra bolt, its a risk-free mod.

It is much harder to make one for an inline gun, since the powertube needs to slide THROUGH the bolt, making it hard to divert to the base. Montneel guns are a bit unusuall in that they use a delayed-bolt, meaning the powertube does not extend through the bolt, so I rigged up this:



Now, does it work? The short answer is "Yes, like the Flatline".

However, it takes a great deal of "tweaking" to get it right.
First, the hole at the bolt needs to be as small, and low as possible. This can be tricky if the bolt has a "SFT" oring. Its easier to use a "no oring" delrin, or nylatron bolt and just cut a groove in the base.

Second, the barrel NEEDS to be overbored from the paint. A general rule of thumb is the barrel needs to be .06-.08 larger then your paint. So, if you have a .690 barrel, you need to use a .682-.684 paint. Basically, the barrel needs to be big enough so that paint can EASILY roll out. If the barrel is not overbored enough, you will get corkscrews as the friction of the barrel alters the orientation of the spin axis

Third, the shorter the barrel, the better. My CooperT on my VM originally had a 18" barrel, and shot like crap. I kept cutting it shorter, and shorter, and shorter. I found that it worked much better with every cut. Actually, there was not much difference when I cut from 7" to 4", so 7"-10" is a good length.

Forth, use hardshell paints. In the 90s, I loved RP "Super Shell", though it hardly broke on players either. Thin shell tournament paints will break alot, just like with the Flatline.

Now, let me be totally honest- It will get you the same effect as the Flatline, and like the flatline, your trajectory will be flat, with a longer maximum range, but your EFFECTIVE range will diminish since accuracy is worse. My theory is that the amount of magnus generated is dependent on the orientation of the seam (like the seam on a baseball), which can not be controlled.

So, with worse accuracy, its not really usefull for long-range woodsball, and with the higher paint breakage, its not really good for high-volume speedball, then why bother?
I found them EXTREMELY useful for playing "Urban paintball" in villages, castles, etc. Any place where you might need to shoot through a series of "windows".

The flat trajectory means that there are places were you can shoot through, where the other player can NOT shoot back because of the arc of his trajectory prevents going through the same location.

Thats pretty much all I know on the subject.

nick

[Railgun]

Alamo City is making "lowblow" bolts for Spyders and some other markers.

The general consensus from folks that report on them is that it does level out the trajectory like you'd expect but the ball will still only break up to the normal range unless you happen to hit something rigid like a mask or exposed shoulder that will still shock the ball into breaking.

So the velocity falls off with distance but the backspin produces lift that holds it up.

My model airplane knowledge and the Law of Conservation of Energy from high school physics tells me that if you use some energy to produce a spin that holds the ball up then you have to use some of the kinetic energy of the ball AFTER it leaves the barrel to hold it up. That means you trade "lift" for impact energy. So your balls may fly further in a level manner but they will have correspondingly less velocity at any given range where the spin is holding it up more than it would have fallen. You see, once the ball leaves the barrel it only has whatever energy you gave it while IN the barrel to work with. If you use that energy to hold the ball up longer than it would otherwise then it has to get that energy from someplace and it gets it from the kinetic energy of it's velocity. So it slows down quicker than a ball fired in the regular way with no backspin.

[rudz]

yes it works, flatlines, apaex, galactic z bodies, now jack rice never had me convinced, but who knows..

[rudz]

Originally Posted by russc

Yep - Alien guns have what Rice calls the "sweep" bolt system, which is exactly the same as what's being discussed here.

i belive the planet eclipse guy was making the "sweep" bolt claim too and tom kaye and doc nickles ripped him a new one, guy had no facts, no proof, only his word..

[HP_Lovecraft]

When I mentioned the CooperT bolt to Jack, he seemed surprised.
Same when I told him about the Epic, or Mollick Rainmaker.

Jack told me that his sweep bolt is different then the CooperT bolt, and more like the Undertow bolt, in that he is NOT trying to generate enough spin to create a "Magnus Effect", but a slower speed to create "Gyroscopic Stability".

His theory, like the Undertow theory, is that an axial spin, will create the same stability as a radial spin, like a bullet fired from a rifled barrel.

Seems a bit "fluffy" to me, but credit goes to Jack for at least trying some unconventional ideas.

nick