Barrel Length Test Results (long barrel vs short barrel) - long post

[Jack & Coke]

After reading a lot of posts regarding the effects of barrel length on the flight of the ball, I decided to run a little test.

Most of the current chatter revolves around "short" (8"-10") barrels vs. "long" (14"-16") barrels.

Before I begin addressing a couple topics, I'd like to state that, much of the myths and misconceptions regarding the physics related to long vs short barrels come from the evolution of the technology behind the barrel itself.

Most of what people have learned about paintball physics comes from research performed at a time when most, if not all, barrels had a single bore diameter. That is, from front to back, the barrel bore size was consistant.

The performance and conclusions from these old style barrels do not always apply to todays new style (step bore) barrels.

When people ask advice about the performance characteristics of "short" vs "long" barrels, they are often given incorrect "old" information.

Why concern ourselves with "new" style (step bore) barrels? Because that's probably what you will MOST LIKELY end up buying if you purchase an aftermarket barrel.

It is useless to compare a 10" barrel with a single bore of .689 to a 16" barrel with a single bore of .689. Why? Because you won't find a common aftermarket 16" barrel with a SINGLE BORE SIZE.

CP Kit, Freak, Dye, Sceptor, Long Bow, Equation, JT, Evil Pipe, etc... ALL are TOP END after market barrels, which you would probably see out there on the field, are step bore designed.

That is, they have a smaller control bore (back), and a larger tip bore (front).

With that said, let's address two of the most common issues regarding "short" barrel vs "long" barrels...

...Efficiency, the longer the barrel the less efficient the gun is because the longer the barrel the more friction there is to over come to get the ball to 280fps...

Wrong.

The amount of friction is the same for TODAY'S after market barrels. The ball has friction on ONLY the control bore (back) of the barrel. It NEVER touches the tip bore.

In fact, a "short" barrel (8"-10") is LESS efficient than a "long" barrel (14"-16") because it requires MORE air to bring the ball up to the same speed.

On a "short" barrel the air pushing behind the ball gets dissipated too quickly. With a "longer" barrel (not too long - there is a point of deminishing returns) the air behind the ball is allowed to peek out it's usefullness.

"...Length of the barrel does not affect range..."

vs.

"...longer barrel = longer distance..."

This is actually true IF you don't re-adjust your regs...

Suppose you chrono your gun to 275 fps with a 10" barrel. If you keep everything the same (i.e. don't touch the regs), and JUST change the barrel, your fps WILL INCREASE a little and you WILL GET a little bit LONGER DISTANCE.:)

However, since we are allowed to adjust our guns to shoot up to a max fps (300 fps), we can make our 10" and 16" both shoot the same speed. Only if you adjust your regs will you shoot the same distance. But then again, it's not really a fair comparison is it? It's like having one runner start 10 yards behind another, slower, runner... say GO! and they cross the finish line at the same time. duh!

The following are results of a little test I did.

I chronoed my mag using just the back of my CP kit (5" control bore), then I shot it with a 12" tip, and then with a 16" tip.

I did the same for my Freak (10" vs 14")

here are the results...

*EDIT* I forgot to mention: for all barrel configuraitons, I NEVER adjusted the regs.

[Jack & Coke]

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[Jack & Coke]

barrels

[Jack & Coke]

Results

[Jack & Coke]

CP Kit length difference has greater effect due to less porting.

Freak results (10 vs 14) are much closer since the AA tip is full of holes.

Conclusion...

For today's aftermarket barrels:

"short" barrels (8" - 10") are LESS efficient than "long" barrels (14"-16")

"accuracy" has more to do with the ball and how it fits the control bore rather than how long the overall barrel is.

"consistancy" has to do with the gun's regs and valve system and how well the paintball matches the control bore of the barrel (i.e. the part of the barrel that actually touches the ball) - not the overall length of the barrel.

[joeyjoe367]

I like the litte "Jack & Coke" plugin there :)

nice post. Good info for newbies.

[Jack & Coke]

Originally posted by joeyjoe367
I like the litte "Jack & Coke" plugin there :)

plug?

No plug.

That there, be some high quality testing equipment!

Only the HIGHEST standard of testing apparatuses shall be deemed worthy of AO!

[TheBigRaguPB4L]

Those 3 cp barrels, are they all the same bore(just for the back, not for the tips). If they differ in bore sizes, i think that might change the results slightly, no? If they are different, try using just one single bore then repeat the test, if you want.

[JEDI]

Jack, first off, very good test. With both barrels the results seem consistent for the first 10 shots (increase in velocity) but then further along in the test the number seem to be all over. Some times the shorties have higher fps, sometimes the longer ones do. What do you think explains this? The test with the 3 CP configurations seems to do the same thing. The first 10 or so shots show a higher fps with the 12" and then a decline with the longer tip, but then further on, the pattern seems to be out the window. I really enjoyed this one. Good job man!

[Jack & Coke]

TheBigRaguPB4L - of course I only used 1 back during all barrel configurations.

The paint was PMI Premiums. The back was a .692. Tonight, I will try the .689 back.

JEDI, I noticed the same thing too! My guess is maybe I did not shoot the gun enough times prior to testing.

Everytime you gas up a gun it takes a few hundred shots before the reg spring (in our case, the x-valve spring) to "settle". I was in such a rush to recrod the test, that i don't think I gave the x-valve enough shots to settle into a consistant seating.

I'll try again tonight!

thanks for the props...

[cphilip]

Interesting argument Jack. But there are a few flaws with the conclusions. A statistician would argue that there is no statisitcal difference at all I should think. There is enough general randomness to suggest that is the more logical conclusion. But even that smacks in the face of conventional wisdom does it not?

And then there is the point that you mention of diminishing returns. And so if you progress outward say to a 16 inch, or even 18 inch, you would likely find you have passed that. And then if you factor that in statisticaly to all the previous you could then conclude that long barrels are less efficent. If you chose to. Because it all depends on where you set the center point. Is that test you conducted concluding a 12 inch is a short and a 14 inch is a long? What happens if that center point shifts out ward and we call a 14" a medium? If so then the center point is 13? Its hard to say realy. So there is more work to be done before we can conclude something on that end. We would have to agree on what short and long is. I might argue a 14 is medium and should be the center point. Or even 15 inch. One may disagree with that. But, as with so many things, it can depend on how many data points you wish to measure. And then where you want to set your center point of comparisons.

But this is good stuff to talk about. My conclusion from you data so far is that it don't matter a whole lot if you use a 12 or a 14. It's negligable. Others may conclude a little differently I guess...

[AzrealDarkmoonZ]

Just a few comments...

The sampling is varied enough to need a few more looks. Also take a look at the effective bore length. I beleive that matters more than say, the actual length of the marker. Sure with a 5" freak compared to a 13" freak you are going to get some more FPS, because even if the Freak does balloon out you are going to get some more push...until you hit the porting, at which point air escapes through the ports.

BTW many cheaper barrels are single bore and not step, Equations Bizerk, Lapcos, CPs at least the classic or whatever they call them nowadays. The LAPCOs are a very common. Of course that is outside the scope of your test, since you were simply comparing step bore. But test the Lapco 11.5" versus a 14" Freak and I would theorize he LAPCO will give better performance.

All in all good work, at least we have numbers and some numbers are better than no numbers, assuming the numbers are accurate.

Az

[Cristobal]

Two thoughts:

1.) the radarchron will introduce a certain amount of measurement error into the results. I think the manufacturer gives a spec of +/- 2% for velocity readings, which sounds good, but at 300fps that's +/- 6fps.

2.) a good way to evalutate the probablility that difference in results from one test to another is purely random would be to run a student T-test on your data. Do a search online and you can find t-test sites where you can insert your data and they'll do the calculation for you.

[battlegroup]

big flaw in the numbers

line 11 has a 398fps for the 16in barrel.

this is obviosly an invalid number for this experiment and should be disregarded. (even though it may be what you actually recorded)

average the 16in cp line without the 398 and the average is 302.74. which is lower than the 12in average.

therefore it completely contradicts your results.

Sorry

[Jack & Coke]

cphilip,

I realize people will interpret "short", "medium", and "long" differently.

I'm not concerned with that.

For my report, I looked at the most comon sizes for aftermarket barrels available today:

8" 10" 12" 14" 16"

"short" = 8"-10"
"medium" = 12"
"long" = 14"-16"

"penis envy" = 18"

Back BEFORE the explosion of the supair tournaments, 12" was considered "standard" (aka medium), and 14" was considered "long" (rare). Now, 14" is probably as common as 12" so many would think this is "medium".

It is not the point of my post to debate this. I'm concerned with 8"-10" vs. 14"-16"

By using a barrel kit with multiple tips, I'm able to keep conditions as consistant as possible without introducing any extra variables. THE ONLY thing different are the tip lengths. Which, in the end, is what we're trying to analyze and understand.

Everytime we offer advise to newbies, exlaining the "differences" between "short" and "long" barrels, I think it would help to actually know what hell we're talking about.

If anyone else wishes to post actual test data, that would be great!

Everthing I have done here, you can do at home and get the same results.

Please, it you have a barrel kit with various tip lengths, please run a test like I did and post your findings here.

If someone other than myself adds their results to this thread, it would further add creditbility and solidify our findings.

:)