Back spin on a paintball

[Old School 626]

Back in the day (90-91) people used to use a little nail polish right at the end of the barrel to impart spin to the ball as it left the barrel. One of the markers of choice during that era was of course the Line SI Bushmaster and if you recall the barrel system would let you orient your barrel anywhere thru 360 degrees. So, you could manipulate your barrel during a game orient that spin for the desired effect, back spin, right/left, etc..

Even on some barrels of the day there was a "grain" within the barrel that would influence the flight of the ball. That is, in my opinion why brass has a following, that surface can be manipulated and polished much easier than others materials.

The internal shape of barrels has always been one of my favorite debates. Today's barrels seem to be mere cylendars and if they are multiple peice barrels they are just cylendars of multiple ID's, there is no real contoured shape to the barrel interior. The shape that I've envisioned as working best would be; The back of the barrel to be large to allow the ball to meet the bore. From the large back the ID would constrict down to a control bore, this would be the tightest portion of the barrel intended to let the ball accelerate under a tight directional control. The next section of the barrel would be un-ported but the ID would be slightly increasing to start to end, releasing the control pressure on the ball and letting it almost float freely in the barrel by the end of the section. The final section of the barrel would be ported and have almost no remaining contact with the ball, the sole purpose of this section would be to let the ball transition from the moving air mass in side the barrel into the still air mass in front the barrel so that the ball's shape would not distort causing the ball's flight path to deviate.

[jade_monkey07]

The internal shape of barrels has always been one of my favorite debates. Today's barrels seem to be mere cylendars and if they are multiple peice barrels they are just cylendars of multiple ID's, there is no real contoured shape to the barrel interior. The shape that I've envisioned as working best would be; The back of the barrel to be large to allow the ball to meet the bore. From the large back the ID would constrict down to a control bore, this would be the tightest portion of the barrel intended to let the ball accelerate under a tight directional control. The next section of the barrel would be un-ported but the ID would be slightly increasing to start to end, releasing the control pressure on the ball and letting it almost float freely in the barrel by the end of the section. The final section of the barrel would be ported and have almost no remaining contact with the ball, the sole purpose of this section would be to let the ball transition from the moving air mass in side the barrel into the still air mass in front the barrel so that the ball's shape would not distort causing the ball's flight path to deviate.

Good post and I agree with the shape of the barrel that you described. Except that a paintball doesnt distort upon firing. even in extreme cases such as this example

http://www.mcbtv.com/media/70/Paintballs_do_not_deform_on_firing/

" The gun was shooting with air at 850 psi, delivered as hard and fast to the ball as is possible. It chrono'd at 381fps. The video was filmed at 20X shutter speed, and 2000 frames per second. You can clearly see that the ball does not deform in any way."

[ThePixelGuru]

Ah, makes sense. Easier to mold plastic to a consistent diameter than it is to simultaneously cut, seal and fill a gelatin capsule to a specific OD.

I do actually love backspin systems though, despite what I said above. Beyond the obvious problems: Terrible accuracy, and breaks paint- It does have one very useful benefit: Flat trajectory. If I'm ever playing any sorta of "village" or "urban" fields. The flat trajectory allows me to shoot through a series of windows, or holes that no other player can shoot back from.

:rofl: Too true. Back when I had my Flatline, I was in the middle of a scenario game when it got finicky on me. For some reason the balls would come out, dive, climb and dive again. Pretty cool swoopy motion to watch, but almost useless for hitting anyone. I was about to walk off so I could calibrate it, but then I found the perfect use - a heavily wooded hill with a stone wall on the top and some of the other team hiding behind it. Everyone was arcing fire into the trees and balls would break before they got halfway to their targets. Well, I started walking around and taking test shots before I got the range just right, but then all my shots swooped right under the tree branches, raced up the hill and dove down over the wall. I must have taken out about half a dozen of them before they fell back. Complete fluke so it's a hard one to take credit for, but my nearby teammates were laughing pretty damn hard when the figured out what I was doing.

[Old School 626]

Jade - re-read my post especially the part just before you quoted in bold, i.e. "in side the barrel into the still air mass in front the barrel." I am clearly talking the ball leaving the barrel not when it's accelerating inside the barrel.

The vid does not really show anything, it's grainy and fuzzy and I don't think you can draw a conclusion about the ball deflecting during acceleration IN the barrel from what is shown.

Sorry to add a pretty worthless post in this forum.

[cadams]

my experience with backspin: I have an Apex tip on my mag and it does make the balls travel farther. However, I have had an increase in paint not breaking on the person I'm shooting at. This has been consistent with my apex tip and my girlfriends flatline. I always use the same brand of paint, and while one batch of paint may be more brittle than other batches of the same make ... it really got me to wondering about the spin making the ball glance off the target rather than breaking properly.

I know have only recently started re-thinking this whole backspin thing. I think I may be taking my apex tip off.

[Castro #66]

Well, seems to me that the bouncing paint issue may be caused by the amount of deceleration the ball experiences over the longer trajectory.

I suppose that it's entirely possible that the backspin may also cause the ball to "pulsate" less while flying through the air, thereby weakening the shell less (comparatively) before hitting the target. This is unlikely, but a theory anyway.

[tech-chan]

WHat if you were to have a very tiny groove that was completely smooth like a little v on the bottom of your barrel? Would'nt that change some of the aerodinamics? Like this:



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[sniper.007]

I seem to remember someone saying a dot or 2 of fingernail polish could be used to give that "apex" kind of spin to the ball once it reached the end of the barrel.
I dont think tape or ball detents are a good idea just because of the paint breaking issue.
I do know that you can always remove or reapply the polish if you need to... so you dont wast a good barrel. Its a idea you can try and if it wont work you are not out to much time or money.

but your wife will think you are going to far when you start looking for it.
"Baby, can I cant find the polish remover."

[Spencer]

I heard of ...

Spit on the top tip of the barrel, lick finger insert..

And tape.. A strip on the top of the barrel..

[ChowderMusket]

A single long groove running the length of the barrel would allow air to bypass the paintball on one side. Would that create an appropriate amount of spin?

[tech-chan]

A single long groove running the length of the barrel would allow air to bypass the paintball on one side. Would that create an appropriate amount of spin?

See, thats what I suggested.... hmmm...

[clemsonpaintball21]

simpler way just take nail polish (clear) and put it on the top of the inside of the barrel when screwed into gun
brush out towards the end of the barrel (btw only ablut 1/2 inch from end of polish)
It will create a backspin on the ball
i did this to my freak kit
LOVE IT

[HP_Lovecraft]

All those ideas were tried in the early 90s, and most were patented.

Ideas like the "extra friction on upper surface", or "extra holes on lower surface" or extra large detents, etc.

Bob Long even released an exotic backspin barrel back in 1993 called the Longshot (unrelated to the modern longshot).

Everyone here also seems to forget the GalaticZ backspin system from the 90s. It used a skid-plate, like what is found on modern Airsoft guns. It does work, though it breaks lots of paint.

Its nice that this old school technology has become popular again with the Flatline, and Apex, but none of the problems associated with backspin systems has been resolved. As such, it still is not much more then a novelty item

[WatchDragon]

How do you spin a liquid filled solid?

[Spencer]

You do..

I don't understand how there are all these tests with rifled barrels and people saying that the paintballs won't spin, however in a flatline they spin just fine..