How long is the ball in the barrel when shot?

[SlartyBartFast]

Alright, the BS flag has already been raised. But think about this:

How on earth could two balls be in a barrel at the same time?

that would mean you would either be opening the bolt while there is still pressure in the barrel. Imagine the blow back.

**EDIT**

Had to take a dig at this ludicrous statement as well:

Originally posted by Miscue
Earon: Rate-of-fire is another point to keep in mind. Back players shoot more paint, so they should look for larger bore diameters to increase their rate-of-fire. Front players need to shoot more precisely, like a BB, rather than more often. They should use smaller bore sizes.

Um... say whut?

I'm with Miscue. What black magic is a larger bore barrel supposed to do to increase the ROF?

I think I know! I has to be so that the balls can not only travel one after the other in the barrel, but so that there's enough room for them to travel side by side!

I think we've gone from BS to absolute certifiable Moron here.

[Top Secret]

Originally posted by SlartyBartFast
Alright, the BS flag has already been raised. But think about this:

How on earth could two balls be in a barrel at the same time

that would mean you would either be opening the bolt while there is still pressure in the barrel. Imagine the blow back.

Also the fact that the first ball would no longer have any air pushing it, causing the next ball to go slamming into it...

[ShooterJM]

Originally posted by Top Secret


Also the fact that the first ball would no longer have any air pushing it, causing the next ball to go slamming into it...

Granted I've seen that before, but that's a blooper shot followed up by a full strength. One of the raceframe videos on here had one I think. Even then, the first shot is out of the barrel by about a foot before the second shot hits it.

[pbjosh]

Man-0-man,

Okay, I did read the total interview. For a guy who makes a great barrel (I love the steelwind and my old school Dye 1 piece) I can't believe the numbers he doesn't know. To bad.

Okay,

For times, take a look at the charts that AGD posted for us in the "Official Data Thread" covering times and pressures behind the ball for various guns. If you look at those time you can figure that the ball takes somewhere between 5-9ms, depending on the gun and barrel length, to make it out the tip from the point that air pressure is applied to the ball.

Since I have numbers for cockers I will use those:

For a gun to cycle at 20 bps it needs to go through its total operation in 50ms

Here is a time line:

20 bps using the settings 7,7,17,10,16 (Halo B or Warp)

1ms after the trigger is pulled the grip solenoid is turned on
3ms after the hammer releases.
5ms after the hammer hits the valve
7ms after the front solenoid is turned on, causing the air to start routing for the 5-way
9-10ms after the bolt starts moving
10-11ms after the bolt has moved far enough that the breech is exposed- allowing for Suction if timed right.
22-23ms after the bolt has moved back far enough that the ball can now pe pushed in by the HALO.
24ms after the bolt has moved back far enough to allow the hammer lug to pass b the sear. At this point, the bolt is fully open.
23-34ms after the ball has been pushed in by the HALO.
34ms after the front solenoid turns off, allowing the bolt to return
50ms after the board allows a new input/shot to happen.

Now, the balls are 50ms apart to run at 20bps. So, given a final speed of 300fps (it doesn't matter how fast they are going at any other point, they all are moving at 300fps 50ms after each other) then the balls would be 15 ft from each other. Having shot paint at near 20bps several times through these cockers, I will say, shooting at close range targets (50ft or so) you can easily see 2 balls in the air, maybe 3, but no more.

unless there are some MAJOR mistakes, there should not be two paintballs in the barrel at once.

Oh, while HALOs take about 5-10ms to load, they only cycle at 45ms, not 4.5ms

on an interesting side note, the Doc9000, which was a Mag mounted on top of a Tippmann Carbine, worked by having the bolt come back and hit the sear on the Mag. The balls fired about 10ft after each other, so the time delay between the shots would be about 30ms.

As for which length barrel is best for each player on the field. Uhm.......... it really doesn't matter. They all should find the barrel that shoots the straightest for them, and that it that. Accuracy has NOTHING to do with ROF. Different issues. The barrel, unless it is horribly in-efficient or breaks paint alot, has nothing to do with ROF. The length of the barrel should depend on what the person wants feels comfortable playing with, that is it. And overall accuracy.

Josh

[the electrician]

ther it is!!

that's it!
Tag it, Bag it, and sell it to the butcher.

that's the best explanation I've read on this topic.

I'd have to say it is another good example of how something can appear to be going faster, or look closer together. because 20 balss are passing the same point in one second, it looks like they are closer than they really are.

[Wat]

This is true at 300fps, but remember a that a paintball can quickly decelerate inflight. The upstream ball will slow before balls behind it will allowing them to catch up. Further out in range when the paintball is moving maybe only 150fps the distance between shots at 10bps is only 15 feet. Just pointing out that the timing between shots is the same, but the distance will not always be the same.

Just like if you watch racing, cars may seem to pull away when they come on to straights or appear to catch up entering corners, but its not the distance between cars that matters but the time.

When i hear of stuff like 2 balls in the barrel at one time, i think if its even mathematically possible and if it is, is it physically possible. The only way you could fire 300fps at 10bps and get two balls in the barrel at the same time is if the majority of the acceleration occured at the end of the barrel. So a ball would move real slow down the barrel, then another ball would be chambered, then the first ball would just hop up to 300fps. But thats not possible as it would imply that you were applying a lot more force to the first ball then the second, which you couldn't do as the second ball is now between the valve and first ball.

Boy, did that not make any sense at all.

Originally posted by ShooterJM


Seems logical to me, I'm betting every one of us has run through a sustained firing lane without getting tagged. 3-4" spacing would be highly improbable to be able to run through.

[SlartyBartFast]

I think you've got it right Wat.

It's impossible because you can't open the bolt to chamber another ball while one is accelerating because you'll release all the pressure in the barrel. This means the second ball in the barrel is would leave the barrel at much less than 300fps and the second ball (if left to accelerate the length of the barrel) would leave travelling at 300fps. Guarenteed that the second would run into (or overtake) the first.

The ONLY way more than one ball will be in the barrel at a time is if you have a 10ft + length barrel.

[J_Hoyt]

How about people start putting down the math they're doing instead of just the answers they're getting. Here's what I've been able to get so far. Equations all look at the motion of the ball while it is in the barrel.

Vi = Initial velocity of ball
Vf = Final velocity of ball
s = displacement of ball (as it applies here, the length of the barrel)
a = Acceleration of ball
t = time the ball takes to reach the end of the barrel

16" barrel = 16/12 feet = 1.333 feet = S value
At the breach, ball is moving 0 FPS. Vi value is 0.
At the muzzle, ball is moving 300 FPS. Vf value is 300.
a and t are unknown values.

Equation 1:
2as = Vf^2-Vi^2
2(1.333)a = 300^2 - 0^2
2.666a = 90,000
a = 90,000/2.666
a = 33,758
Average acceleration of ball in a 16" barrel is 33,758 FPS/s.

Equation 2:
Vf = Vi + at
300 = 0 + 33758t
t = 300/33758
t = 0.009
Ball reaches end of 16" barrel in .009 sec or 9 milliseconds.

Vf = 300 FPS
Vi = 0 FPS
s = 1.333 feet
a = 33758 FPS/sec
t = 0.009 sec
Now we have a good description of the motion of the ball while it is in the barrel.

If 1 ball was to be shot every 0.009 seconds, then every 0.009 seconds there would be a ball in the breach beginning to accelerate at that instant and a ball at the muzzle. 2 balls in the barrel every 1/0.009 balls per second or 111.111 balls per second.

I welcome you to correct any mistakes you find in my math or logic.

Joel Hoyt

[Koosh]

Heh... Before anyone else says it...

Welcome to AO Joel! I was never a physics guy myself, so I don't know aboot your equations... but from me, they look good, so I guess thats all that matters!

[J_Hoyt]

Thanks. I think I'll like it here. :) I dont own a mag or anything but I heard this is a good place for some harcore tech talk. I also came up with another solution.

*ahem*

here it is....

"We can't shoot 100 balls a second so it doesn't really matter."

Pretty good, eh?
Joel Hoyt

[petefol]

i just learned about all that acceleration stuff in physics and it looks about right to me. but anyway, you would think a guy who makes some of the (claimed to be) best barrels, he would be a little more right.

[pbjosh]

Yes, welcome Joel.

Feel free to drop #s or anything else. The PBworld needs more numbers than it has.

Josh

[confedman75]

Originally posted by Top Secret


Also the fact that the first ball would no longer have any air pushing it, causing the next ball to go slamming into it...

not necesaraly once the second ball get to wear the first ball used to be it will be going as fast as the first ball when ti was right there so thus the second ball will never hit the first because the second ball slows down just as fast as the first

[EchoX]

How come people say that the second ball will hit the first ball? Won't momentum and the rest of the air behind it take it the rest of the way. It's not like it's gonna slow down dramatically. People can still shoot paintballs with 8" barrels, so there'll be a sufficient amount of acceleration.

[SlartyBartFast]

Originally posted by confedman75
once the second ball get to wear the first ball used to be it will be going as fast as the first ball when ti was right there so thus the second ball will never hit the first because the second ball slows down just as fast as the first

Not so. Under discussion is the impossible scenario of two balls being in the barrel simultaneously. The second ball will have air pushing it for the whole length of the barrel but the first only up to the point at which the second supposedly enters the barrel.
The second ball then experiences more accelration and would hit the first.