A ported barrel/ length question

[Willystyle21]

I've been reading through alot of posts and for the most part they all seem to agree that barrel porting is pointless except for turbulence issues ie: getting the turbulence from out of in front of the paintball while still inside the barrel.
Now my question.
Been thinking about this for a while and have read that at the very first port of the barrel you lose all pressure behind the paintball ( the same as you would at the end of the barrel with out porting). Lets say for arguments sake you have 100 psi released from the bolt.
1. As the ball begins down the barrel, air pressure builds up in front of it.
2. As it travels done the barrel as much excess pressure as the porting will allow will be expelled through the ports.
3. As the ball passes across the ports some pressure is lost, however the full extent of the 100 psiwould not be lost becross 100% of the porting ( to include the end of the barrel once the paint leaves it) has not been passed. 4. Obviously some preesure from the bolt is lost but untill the pressure from the bolt fully reaches the outside of the barrel AND equilizes with the ambient pressure the paint ball will continue to speed up, not slow down as I have read in several posts.
So even though barrel lengths dont really do anything for increased accuracy( except maybe having less wind hit the ball while it is on its way to the target). With the correct amount of porting and the most functionally correct Paintball ( that a ball shape can be). Perhaps more accuracy can be gained.
As I have suggested in another post, maybe a teflon based shell with a scored shell (longitude lines on a globe) and a thick latex based paint, we might see something.

Correct me if I am wrong.

[athomas]

Actually, porting is just a nice way to make a barrel more quiet. A tiny bit of porting at the very end of a barrel can help relieve uneven pressure from an odd shaped ball, but generally will not help much with the overall accuracy of good quality paintballs.

There isn't much turbulence built up in front of a paintball moving down a barrel. The low pressure air in front of the ball offers no real resistance and moves out the barrel in front of the ball without building up any significant pressure.

As for accelerating a ball once it has passed the porting, this varies from barrel to barrel depending on the amount of porting. A heavily ported barrel may allow air to escape very easily and will therefore offer no pressure behind the ball after it reaches the porting. A slightly ported barrel may still have a bit of pressure behind the ball after it reaches the porting. If the pressure results in more force behind the ball than frictional forces acting against the ball, then you will get additional acceleration down the barrel until the acceleration force reduces to an amount less than the frictional forces.

An easy way to see how much the ports affect the acceleration of the ball is to put a ball in the barrel past the porting. Now blow into the breach end of the barrel. Can you cause the ball to accelerate out the end of the barrel or does the air just vent out the ports?

Efficiency is the biggest thing that can be gained by having the proper length barrel and the correct amount of porting. Properly utilize the acceleration curve for your bolt setup before venting the excess air pressure.

[SlartyBartFast]

Re: A ported barrel/ length question

Originally posted by Willystyle21
I've been reading through alot of posts and for the most part they all seem to agree that barrel porting is pointless except for turbulence issues ie: getting the turbulence from out of in front of the paintball while still inside the barrel.

ONLY thing barrel porting does is shorten the effective length of the barrel and make the barrel quieter.

Originally posted by Willystyle21
With the correct amount of porting and the most functionally correct Paintball ( that a ball shape can be). Perhaps more accuracy can be gained.

Correct me if I am wrong.

[Willystyle21]

Slartly:
What I was saying is that I have read often that the main reason for the porting was to remove the turbulence. I realize that in no way does porting affect spin or accuracy of the ball. I meant to remove as much as possible not all of the pressure in front of the ball. And as long as the is a greater amount of air pressure behind the ball than there is in front of it the ball will continue to accelerate no matter where it is (in barrel or not). And I also have a idea to apply negative pressure to the front of the barrel to aid in this.

By "functionally correct ball" I meant just what I suggested, by adding mass to the ball as well as score lines ( whch was indepthly discussed in the "look ma a dimpled paintball" thread). These would in my idea based upon what I have read, (remember I have no knowledge of fluid dynamics just astrophysics), would help with inaccuracy caused by ambient air, teflon to reduce friction and score lines to reduce turbulence in the wake of the ball flying through the air.

I also meant by my post is that if you lower the friction coiffiecent ( of the barrel and ball) acceleration will result as well as eficiency. Which is allways wanted.

[SlartyBartFast]

Originally posted by Willystyle21
What I was saying is that I have read often that the main reason for the porting was to remove the turbulence.

No, that was the original crappy marketing hype from SP. Now all barrels have it because everyone likes a quiet barrel and expects porting.

Changes to the paintball fabrication process may help with flight dynamics, but why bother. The cost would be too high.

Paintballs are fairly cheap, and perform adequately for their purpose.

Unless you want to be a woodsball sniper.

And you can't remove pressure from in front of the ball. That's just natural aerodynamics. Pressure in front of a moving object in proportion to the objects speed.

[Willystyle21]

Unless you want to be a woodsball sniper.

Exactly..............

I am the type of guy that will strive to get every single horsepower out of an engine. If you know what I mean, and besides when it first started wasn't making semi's and then electro's high cost? Just takes time. And anyone know how much difference in price the paint fill is now compared to a latex based one?

[schapman43]

What about putting dimples on a paintball like a golf ball. I know the dimples on a golf ball supposedly help it in flight. I think dimples could easily be added in the manufacturing process.

More gold ball dimple info.

http://wings.avkids.com/Book/Sports/instructor/golf-01.html

[Willystyle21]

Uh.............

Go to the "Look Ma a dimpled paintball" thread first. Then you an find out the answer to the question.

[Paladin]

Actually, muzzle breaks and venting was originally done to paintball barrels to help get the pressure off the back of the ball before leaving the control of the barrel.
Any gas/air that is still pushing on the ball as it leaves the barrel can have an adverse effect on the flight path of the ball. Venting give the ball a chance to get away from the following air pressure.
A long venting pattern is just a long muzzle break that vents slower and thus more quietly.
The better the gun is tuned so that the air runs out of "push" before the ball gets to the end of the barrel, the less effective a typical muzzle break will be.

[Miscue]

There are high speed pics somewhere, where the ball exits ahead of the air blast - so I'm not quite understanding how this works. Air molecules collide with other things in an elastic collision. It's the air molecules bouncing around in a container that result in air pressure.

So, this should be comparable to other elastic collisions. Such as when you hit a baseball with a bat - although the ball leaves the stadium, the bat is always behind the ball and has a short duration of impulse force.

[Miscue]

Re: A ported barrel/ length question

Originally posted by Willystyle21
1. As the ball begins down the barrel, air pressure builds up in front of it.
2. As it travels done the barrel as much excess pressure as the porting will allow will be expelled through the ports.
3. As the ball passes across the ports some pressure is lost, however the full extent of the 100 psiwould not be lost becross 100% of the porting ( to include the end of the barrel once the paint leaves it) has not been passed. 4. Obviously some preesure from the bolt is lost but untill the pressure from the bolt fully reaches the outside of the barrel AND equilizes with the ambient pressure the paint ball will continue to speed up, not slow down as I have read in several posts.

The ball gets shot out like a cork. Air pressure doesn't build, it is suddenly released - letting out all the energy really quickly - and then it dies out just as suddenly.

Put a ball on the end of your barrel and shoot it - an unported barrel if you got one, like a stock mag barrel. VERY big difference from shooting it normally eh? This is because a majority of the energy from the air blast has been spent well before it has a chance to reach the end of the barrel... a barrel which acts as a pressure chamber - and the regulated air that enters this chamber gets reduced in pressure at an exponential rate as the pressure chamber increases in size (ball moving down barrel). Going from 300fps, to lobbing a few feet in front of your feet is a sign of this exponential drop in energy.

Porting, or no porting... the required energy imparted on the ball to accelerate it to 300fps has already been released before it even gets that far - the porting makes no difference because the job is already done.

[SlartyBartFast]

[Paladin]

"It has never been shown that pressure behind the ball has any effect on the paintball once it leaves the barrel. "

But it has been shown, just maybe in not a way that you would/could see it.

If you shoot a paintgun from a firmly fixed position and establish an average for the size of the shot group that results and then add an apliance the end of the barrel that results in a measurable reduction in the size of the shots groups, what would that show you ?
Also consider that the averages were/are establized by dozens of shot groupings and the tests performed on dozens of different guns with a broad range of configurations and all showed similar improvements.

On another point; comparisons of ballistics and propulsion dynamics for rigid and aerodynamic projectiles as a basis to define those elements relating to flexible and not so round projectiles as paintballs dose not prove anything either.

[trains are bad]

Flash suppressors, which may or may not perform some of the function of a muzzle brake, serve to catch and burn unspent powder and gases so that the flash does not give away the shooters position.

Not really. It might be a side benefit. It's really obvious where fire is coming from at night, flash supressor or no. Besides the NOISE factor...

The real purpose of the flash suppressor is to direct the flash away from the sightline so the shooter can see after the first shot, and doesn't get those streaky looking lights in his head and lose night vision.

My mini 14 spits a beachball sized muzzle flash unsupressed, which totally kills your eyes if it's dark out.

[SlartyBartFast]

Originally posted by Paladin
But it has been shown, just maybe in not a way that you would/could see it.

If you shoot a paintgun from a firmly fixed position and establish an average for the size of the shot group that results and then add an apliance the end of the barrel that results in a measurable reduction in the size of the shots groups, what would that show you ?

Sorry Paladin, but that's garbage. If it's true it can be shown.

If you have such an appliance and test results proving it works, then why don't you sell it?

If the flash and escaping gases from a firearm balloon out and away from the projectile, whta bizzare deformation of space/time ocurs to make the air escaping at the end of the barrel effect a paintball?