[UV Halo]

Jack Wood, on Aug 7 2009, 10:19 AM, said:

...can produce porting where the total surface area of the ports is Greater than the surface area of the bore of the barrel.

I'm confused by this description as I can interpret it in two ways:
1. The sum of the interior surface area removed during the porting process > than the remaining interior surface area? (a barrel where you have more material removed, than remaining, like that old rail-based barrel).
2. The sum of the Ported Surface area > the area of the non-ported surface area (i.e. 8" of porting on a 12" barrel).

brycelarson, on Aug 7 2009, 11:32 AM, said:

The stock Phantom barrel for example - it's minimally ported but quite quiet. I think the key might be the channels - they act as a significant step up for the last 1.5" or so.

I don't own a phantom and I've not seen a phantom barrel up close, can you point me to a description or diagram showing this? What I'm picturing is interior grooves (fluting) inline with the length of the bore, for the ported section of the barrel.

[brycelarson]

UV Halo, on Aug 7 2009, 03:18 PM, said:

Jack Wood, on Aug 7 2009, 10:19 AM, said:

...can produce porting where the total surface area of the ports is Greater than the surface area of the bore of the barrel.

I'm confused by this description as I can interpret it in two ways:
1. The sum of the interior surface area removed during the porting process > than the remaining interior surface area? (a barrel where you have more material removed, than remaining, like that old rail-based barrel).
2. The sum of the Ported Surface area > the area of the non-ported surface area (i.e. 8" of porting on a 12" barrel).

brycelarson, on Aug 7 2009, 11:32 AM, said:

The stock Phantom barrel for example - it's minimally ported but quite quiet. I think the key might be the channels - they act as a significant step up for the last 1.5" or so.

I don't own a phantom and I've not seen a phantom barrel up close, can you point me to a description or diagram showing this? What I'm picturing is interior grooves (fluting) inline with the length of the bore, for the ported section of the barrel.

to the first part - the sum area of all of the ports cannot exceed the area of the barrel - ie the bore of the muzzle of the barrel. so, if the barrel is a .690 - then there cannot be more than .37 square inches.

the phantom barrel has only a modest amount of ports - http://www.phantomon...uns/barrels.htm

only 4 holes per row with 8 rows of porting. inside the barrel there are flutes cut into the barrel - about the same length as the porting from the end of the barrel. those flutes line up with the porting. they're about 1/16" deep and a little less than 1/8" wide. so, looking at the front of a phantom barrel - it looks a bit like an 8 pointed star - with each point lining up with a row of porting.

[UV Halo]

That explains it perfectly! I now see that this is the same patent that described the helical porting.

I would be surprised to hear that a Phantom sounds quieter than an equally ported barrel without the grooves.

[Dragon1291]

Bryce... You lied.... You said a minute....

I guess the only way to test the porting issue is with a freak kit... I mean, don't they have a rain tip and crap?

[Jack Wood]

I can give you another bit of information (if you can call it that):

When we were very very friendly with WDP we were shooting Jacko barrels (1-piece stepped bore, very very clever) and we wanted rain barrels (we live in England!) so they made us 1-piece stepped-bore barrels with zero porting.

They were terrible. I don't just mean an anicdotal "not as accurate". I mean shoot-round-corners absolutely un-shootable. I mean un-shootable. More inaccurate then having a break and rain in a barrel.

Bryce, I would be interested to see a test with the Freak Rain tip. Does it have zero porting?

[thumper]

great video.. good summary..

Ive have had a long standing opinion that the (acceleration + recovery) time needed is a function of operating pressure.

the higher the initial pressure, the more rapid the acceleration, the shorter the barrel needed to fully the accelerate the ball efficiently (e.g., automags)
the lower the initial pressure, the slower the acceleration, the longer the barrel needed to fully accelerate the ball efficiently

[Blue mInI]

D.K., on Aug 6 2009, 10:34 PM, said:

Hopefully I just educated some people in the chat with this thread.

Thanks Bryce!

Is a .684 a good underbore, because i already have a Dye UL kit going and dont want to spend too much to figure out if underbore will work for me, and Dye only makes up to a .684, unless someone knows where i can get a .682 from DYE????

[Troy]

Jack Wood, on Aug 8 2009, 02:37 PM, said:

I can give you another bit of information (if you can call it that):

When we were very very friendly with WDP we were shooting Jacko barrels (1-piece stepped bore, very very clever) and we wanted rain barrels (we live in England!) so they made us 1-piece stepped-bore barrels with zero porting.

They were terrible. I don't just mean an anicdotal "not as accurate". I mean shoot-round-corners absolutely un-shootable. I mean un-shootable. More inaccurate then having a break and rain in a barrel.

Bryce, I would be interested to see a test with the Freak Rain tip. Does it have zero porting?

I don't know what to think about this, it's hard for me to imagine how porting would effect shots THAT much... not that I'm doubting you, I'm just at a loss.

[Troy]

thumper, on Aug 9 2009, 06:21 AM, said:

great video.. good summary..

Ive have had a long standing opinion that the (acceleration + recovery) time needed is a function of operating pressure.

the higher the initial pressure, the more rapid the acceleration, the shorter the barrel needed to fully the accelerate the ball efficiently (e.g., automags)
the lower the initial pressure, the slower the acceleration, the longer the barrel needed to fully accelerate the ball efficiently

I think this is something that should be looked into, I'd like to see a test with barrels with different control bore lengths between markers with different operating pressures. A mag may be a confusing example, because of it's lower breech pressure, but a test between a Tippmann and a Droid/Geo/Quest/(name your lp spoolie) would be interesting.

[brycelarson]

Troy, on Aug 9 2009, 08:46 AM, said:

I think this is something that should be looked into, I'd like to see a test with barrels with different control bore lengths between markers with different operating pressures. A mag may be a confusing example, because of it's lower breech pressure, but a test between a Tippmann and a Droid/Geo/Quest/(name your lp spoolie) would be interesting.

I don't know that we actually have breech pressures for too many modern guns. Tom Kaye did a bunch - but that was back a while ago. The problem with the test is that it involves cutting into guns - so it would be really, really expensive. And operating pressure doesn't necessarily have much to do with breech pressure. In the old test (this is off the top of my head - so I might be a bit off) - the angel was the highest breech pressure at 110 psi or so. the Mag was at the lower end at about 60 psi - with a much more gradual power curve - while the cocker was in the middle at 80-ish.

It's been a while so I may be off on those - but I'm pretty certain about the mag and angel - they were sorta the point of the test - TK was showing that operating pressure isn't the same as breech pressure.

but yes, threre should be some relationship between optimal control bore length and breech pressure - the higher the shorter.

The other possibility is that there is something else at work here. Paintballs accelerate really rapidly - a matter of just a hand-full of milliseconds. It's possible that the optimal lengths aren't different enough to matter. I'm totally making these numbers up - so don't take them as some sort of endorsement - but it's possible that the lowest breech pressure of, say 50 psi and the highest at 110 - a ratio of more than 2:1 - might only have a .5" difference in optimal length. say a 10" control bore and a 9.5" control bore.

Since the pressure drops so quickly behind the ball as it moves - the starting pressure will start to even out. so, let's take that same example, 50 and 110 psi.

after the volume behind the ball has doubled now we're looking at 25 and 55 psi, double that again and we're at 12.5 and 22.5. double it again and we're at 6.25 and 11.25. so now we're still at a ratio of 2:1 - but the psi differences are tiny - only 5 psi at this point - so it's possible that the only significant difference goes away so quickly that the optimal acceleration length just isn't that different.

[MNpaintball]

so based off of what you now know (or what you have known,) what would you think right now for the money is the best barrel out there that does it's job, and does it well?


oh, and a great vid overall i must add. there are going to be people that are going to call "BS" because they will find out their SLY kit or UL barrel isn't worth the money (statistically)

[brycelarson]

mnpaintball, on Aug 9 2009, 09:26 AM, said:

so based off of what you now know (or what you have known,) what would you think right now for the money is the best barrel out there that does it's job, and does it well?

well, let's see. either a 1 piece or a kit with a long back - overall length 12-14".

CP .685 12" or 14"
CP two piece kit - .682
Freak Jr. in .679+.682

I have a 14" stiffi in .681 here - have not shot it yet - but should be good stuff. 5.5" of .681, then steps up to .700

by my theories the deadly wind CF barrel should be good - along with any kit with long backs (evil pipe kit etc.)

technically the one piece barrels win on efficiency - but since virtually none are what I would consider small enough - I can't just say 1-piece. they tend to be much better price/performance wise. Any small bore one piece you can get our hands on is a good move.

[FireFrenzy]

I felt like i was back in all sorts of review papers or abstracts from the reading i have to do for my internship... and here I was thinking i had a vacation:P Very well done vid with a good review portion of the availible data...

[Troy]

brycelarson, on Aug 9 2009, 08:59 AM, said:

after the volume behind the ball has doubled now we're looking at 25 and 55 psi, double that again and we're at 12.5 and 22.5. double it again and we're at 6.25 and 11.25. so now we're still at a ratio of 2:1 - but the psi differences are tiny - only 5 psi at this point - so it's possible that the only significant difference goes away so quickly that the optimal acceleration length just isn't that different.

This is exactly why I would like to see it tested. I would really like to see how breach pressure relates to bore length... but like you said, operating pressure and breach pressure don't necessarily correlate so breach pressure would have to be tested first.

I would love to see the breach pressures for a bunch of markers posted up... figuring out if that effects control bore length would be gravy.

Is there any reason why you couldn't drill into a barrel and put a sensor there as close to the breach as possible instead of drilling into the marker? Yes, you'll prolly get slightly lower pressures than TK did, but you wouldn't have to scrap an otherwise perfectly good marker. As long as the distance of the placement of the sensor, the bore size of the barrel, and the diameter of the paint were consistent, than I would consider this an acceptable measure.

Furthermore, I think this would be a cool way to test the different breach pressures that result from different paint/bore combinations... which would be cool to know as well.

[maddog3904]

Jack Wood, on Aug 8 2009, 03:37 PM, said:

I can give you another bit of information (if you can call it that):

When we were very very friendly with WDP we were shooting Jacko barrels (1-piece stepped bore, very very clever) and we wanted rain barrels (we live in England!) so they made us 1-piece stepped-bore barrels with zero porting.

They were terrible. I don't just mean an anicdotal "not as accurate". I mean shoot-round-corners absolutely un-shootable. I mean un-shootable. More inaccurate then having a break and rain in a barrel.

Bryce, I would be interested to see a test with the Freak Rain tip. Does it have zero porting?

I own both the rain front and the AA front, so I can give some information on this. The rain front does have zero porting (hence rain front), however I have found that this has made no impact on accuracy. The major difference between the rain front and the AA front is the direction of sound. Without porting, all the noise is directed forward out the barrel, toward the target. It sounds about the same as the AA front to the shooter, but if you stand down range you can tell the difference. My personal choice between the two is the rain front. The reason? Its extremely easy to clean barrel brakes....Of which I've never had while playing.

[brycelarson]

maddog3904, on Aug 10 2009, 09:11 AM, said:

I own both the rain front and the AA front, so I can give some information on this. The rain front does have zero porting (hence rain front), however I have found that this has made no impact on accuracy. The major difference between the rain front and the AA front is the direction of sound. Without porting, all the noise is directed forward out the barrel, toward the target. It sounds about the same as the AA front to the shooter, but if you stand down range you can tell the difference. My personal choice between the two is the rain front. The reason? Its extremely easy to clean barrel brakes....Of which I've never had while playing.

do you have a backyard to shoot in? Can you do a 50' test - just grid up some plywood, lock the gun down and shoot 20 shots with each front?

[NovaPB]

The only problem with under boring is it is not trivial to do. The ability to under bore is dependant on the paint available (i.e. field paint) to you and the limited selection of barrels on the market. If you can't get a real under bore, you may be inadvertently matching. Since barrel/paint matching results in worst consistency, this needs to be avoided. Thus, under boring needs to be avoided unless you can be sure you are truly under boring. If you cannot reliably under bore, your next best option is to overbore.

Basically, you cannot just say buy barrel X and you will be under boring. The wise player will still have an under and over bore barrel and check the paint when they play.

Point in case, the paint we had to use at the BT Big Game on Saturday either rolled out of my 0.682 CP 2 piece or wedged in tight (needed a squeegee to push out). Paint was rolling out of 0.679 freaks as well. Performance from my 0.682 was terrible. The chrono was all over the place as well.

While I agree with under boring in theory, until barrels become available to get a true under bore, IMO you are better off taking the efficiency hit and over boring than risk the poor consistency of a paint/barrel match. Ironically, you should do exactly what the manufactures recommend via their stock barrels and over bore.

This post has been edited by NovaPB: 10 August 2009 - 09:32 AM

[Special Ed]

UV Halo, on Aug 7 2009, 03:18 PM, said:

Jack Wood, on Aug 7 2009, 10:19 AM, said:

...can produce porting where the total surface area of the ports is Greater than the surface area of the bore of the barrel.

I'm confused by this description as I can interpret it in two ways:
1. The sum of the interior surface area removed during the porting process > than the remaining interior surface area? (a barrel where you have more material removed, than remaining, like that old rail-based barrel).
2. The sum of the Ported Surface area > the area of the non-ported surface area (i.e. 8" of porting on a 12" barrel).

brycelarson, on Aug 7 2009, 11:32 AM, said:

The stock Phantom barrel for example - it's minimally ported but quite quiet. I think the key might be the channels - they act as a significant step up for the last 1.5" or so.

I don't own a phantom and I've not seen a phantom barrel up close, can you point me to a description or diagram showing this? What I'm picturing is interior grooves (fluting) inline with the length of the bore, for the ported section of the barrel.

Here's some pics showing the inside of the Phantom barrel. There are channels for all the ports as well as a slight step increase of the ID.

[brycelarson]

thanks ed.

[nickp]

Okay i just have a question. When you shoot a paintball out of the barel while under boaring the paintball will squeze into the barrel creating a oblong shape and when it comes out of the end of the barrel its going to try to change shape during in flight which will cause some drag and turbulance. Wont this cause a decrease in acuracy? I know with underboaring this will still happen but not as much so overboaring is more acurate?