one piece better than two piece?

[AutomagBoy]

Wouldn't a one piece be more accurate than a 2 piece because the one peice fits the ball for the enitre barrel? Rather than a 2 piece fitting a ball for only 4 inches of the barrel?

[ß.C.]

I have that exact same question in mind . . .

[FalconGuy016]

Id like to know too

[RRfireblade]

All else being equal,the length of the control bore has little to do with accuracy and everything to do with efficiency.

Jay.

[Miscue]

Nope... but one-piece is more gas efficient.

[MarkM]

Originally posted by Miscue
Nope... but one-piece is more gas efficient.

And this would be why? Two-piece doesn't mean great big hole between the two parts, given that Tom has stated that is the first ?? inches that make the difference....we are in general past that point in a two-piece design. So all the gas used to reach that point has been used so after the ?? point then efficiency is a mute point for a one or two piece. If you mean that due to the nature of two-piece barrels that tend to be of a much larger section after the control bore section then an inefficience may then show up. And since a one-piece barrel is again in general the same bore for the entire length (I know there are exceptions to this) then surely the drag factors would actually make this the most inefficient of the two designs. All this is not taking into consideration the step bore one-piece barrels that are made where different math would have to be done to find the result.

[nerobro]

I've never seen any "real" testing on the subject. But my guess is that a one peice will shoot more balls with less spin than a barrel with a two stage bore.

[magman007]

well you see, once the ball has reached its maximum velocity within the first few inches, the gas keeps it there throughout the barrel til hitting porting, once you hit that your gas escapes, also at porting in a single boare, the bore gets larger, creating your step bore.

[RRfireblade]

Originally posted by nerobro
But my guess is that a one peice will shoot more balls with less spin than a barrel with a two stage bore.

So you think the longer the ball skids down the length of the barrel the LESS chance of spin?

Interesting.

Jay.

[BlackVCG]

Originally posted by AGD

So as far as our guns are concerned, the best efficiency would be had with an 8-10" effective length barrel. Since two piece ported barrels with an effective length of about 5-6" are the rage right now you hear a lot of complaints about gas efficiency. Under some circumstances there is a good reason to use a short effective length barrel. Short barrels cut off the acceleration abruptly by venting and this has the effect of tightening up the shot to shot velocity variation. If you need this at the expense of efficiency then go ahead. Tighter velocity control usually translates into some improvement in accuracy due to better consistency.

AGD

[Miscue]

Originally posted by MarkM


And this would be why? Two-piece doesn't mean great big hole between the two parts, given that Tom has stated that is the first ?? inches that make the difference....we are in general past that point in a two-piece design. So all the gas used to reach that point has been used so after the ?? point then efficiency is a mute point for a one or two piece. If you mean that due to the nature of two-piece barrels that tend to be of a much larger section after the control bore section then an inefficience may then show up. And since a one-piece barrel is again in general the same bore for the entire length (I know there are exceptions to this) then surely the drag factors would actually make this the most inefficient of the two designs. All this is not taking into consideration the step bore one-piece barrels that are made where different math would have to be done to find the result.

Cuz I said so. ;)

Two-piece barrels typically have 5-6 inch control bores... the tip is not "effective" barrel. One piece barrel has longer effective barrel length. Longer effective barrel allows more time for ball acceleration... Shorter barrel must use more air to increase acceleration rate to hit final velocity sooner. Increased barrel length results in dimishing returns, being optimal at around 8-10 inches. Acceleration rate of ball dwarfs negligible deceleration from both air and barrel coefficient of friction.

[RRfireblade]

Originally posted by Miscue


Cuz I said so. ;)

Two-piece barrels typically have 5-6 inch control bores... the tip is not "effective" barrel. One piece barrel has longer effective barrel length. Longer effective barrel allows more time for ball acceleration... Shorter barrel must use more air to increase acceleration rate to hit final velocity sooner. Increased barrel length results in dimishing returns, being optimal at around 8-10 inches. Acceleration rate of ball dwarfs negligible deceleration from both air and barrel coefficient of friction.

That's very subjective,
with the exception of Lapco and some stock barrels(which are usually very large bore anyway)in most one peice barrels(assuming it's unstepped which basically makes it like a 2 piece)there is usually only 5-7 inches of unported length,basically equal to many 2 piece after which the friction has a negitve effect whereas a 2 peice stepped bore requires a similar acceleration but with out the added friction in the last portion.

Jay.

[joeyjoe367]

If it were up to me, I'd have a 1 pc CP barrel for every bore size, and every length. Maybe even every color, but hey, I'm dreaming right? I can want whatever i want ;)

CP's have about 8" of unported barrel length (perfect a la AGD) making them pretty efficient.

[Miscue]

Originally posted by RRfireblade


That's very subjective,
with the exception of Lapco and some stock barrels(which are usually very large bore anyway)in most one peice barrels(assuming it's unstepped which basically makes it like a 2 piece)there is usually only 5-7 inches of unported length,basically equal to many 2 piece after which the friction has a negitve effect whereas a 2 peice stepped bore requires a similar acceleration but with out the added friction in the last portion.

Jay.

This is plain wrong.

Where the heck is everyone getting this silly idea on friction?

The friction DOES NOT MATTER... it's there, but it's a negligible force.

Barrel A: 5" effective
Barrel B: 9" effective

Situation: Use same exact volume/psi of air using both barrels. The velocity of a ball in barrel A and barrel B at 5" will be identical. Barrel A ends acceleration at 5", while Barrel B is STILL accelerating. Acceleration = still getting FASTER, remember. The exit velocity of barrel A will be lower than barrel B, even though same amount of propellant was used. To fix this, you have to use more air with barrel A = less efficient. Like I mentioned before, with diminishing returns... it gets to a point where a longer barrel is no longer beneficial... and AGD has noted it to be around 8-10 inches.

The coefficients of friction of the ball and barrel will be very low. The work done by friction will be completely dwarfed by the work done by propelling the ball. If a train runs through an oncoming car head on... it's not going to have a big effect on it.

As far as your porting comment goes... you're getting into unnecessary precision wherein what I explained was sufficient in explaining the general idea. Porting is an exceptional case. Seal off the porting (which is another exceptional case, and not far-fetched) and then you got your 8-10" effective barrel on your one piece.

There's a lot of "what if's." I was shooting for a description of the general case - which is pretty much the important one.

[AutomagBoy]

sooo, whats more accurate one piece or two? This should be moved to deep blue.

[cphilip]

I thought this was going to be about Bathing Suits!

And on that note...a one peice Bikini is better than a two Peice Bikini... :D And better yet a Camoflage Bikini!!!! :eek: :cool:

[shartley]

Originally posted by cphilip
I thought this was going to be about Bathing Suits!

And on that note...a one peice Bikini is better than a two Peice Bikini... :D And better yet a Camoflage Bikini!!!! :eek: :cool:
T-shirt and bikini bottoms. Nuff said. :D

[FeelTheRT]

Originally posted by joeyjoe367
CP's have about 8" of unported barrel length (perfect a la AGD) making them pretty efficient.

mine has 10" of un-portedness ;)

[cphilip]

Originally posted by FeelTheRT


mine has 10" of un-portedness ;)

Heh! You wish!!! ;)

[MarkM]

Originally posted by AutomagBoy
sooo, whats more accurate one piece or two? This should be moved to deep blue.

This isn't the debate, if one barrel is more efficient than another the net result "should" be a more accurate barrel. That is to say that should barrel A be a very friction free barrel then the paintball will exit the barrel at its optimium speed ball after ball, should barrel B be very "sticky" then the deviations needed to be overcome would then result in the barrel being more inaccurate.

Miscue....friction does matter, it effects the mass velocity aceleration. The same pricinples are employed in the gas flowing of "performance" cylinder heads within the automotive industry and various other components found in the engines.

Don't be moving this into Deep Blue, unless we all start posting formulae equations to prove our various ideas.

[Miscue]

Efficiency and accuracy do not have a direct correlation. TK notes that a shorter, less efficient barrel has tighter velocity control, which generally translates into some improvement in accuracy. I would think that "some" is more on the lines of "negligible." A minor improvement in velocity control doesn't do a whole lot to overcome the inherant inaccuracy of a paintball... a blunt object with poor aerodynamic qualities.

Changing Barrel B to a sticky barrel makes things unequal... why not put a barrel plug in barrel B too while you're at it? This doesn't make any sense.

I agree, friction "matters." However, the energy lost due to friction from barrel/ball contact is very small in comparison to what is put into propelling the ball.

Hold a barrel vertically, and put a ball in it. If the ball falls through, the deceleration on the ball caused by friction from barrel contact is less than 9.8 m/s^2, the approx. pull of gravity at standard ATM. Use a barrel that fits the ball just enough to keep it from falling, and the deceleration is around 9.8 m/s^2. Use a barrel that's very tight, and the deceleration will be above 9.8 m/s^2.

So, using a properly fitting barrel will result in, let's say, about a rounded 10 m/s^2 deceleration. Now, a paintball can have an instantaneous acceleration of 15240 m/s^2 (50,000 ft/sec^2) to hit 300fps in 10 or so inches. 15240 - 10 = 15230... Whoopty doo. Either way, it's PLENTY to get a ball up to 300fps... the slight loss doesn't matter.

More importantly, this loss is not cummulative. It's one drop in the bucket. Next ball, get a new bucket and start over.

Your reference to an engine is - irrelevant in understanding what goes on in a PB gun. If you fired a cylinder ONE time and measured loss of energy due to friction vs. a better designed engine... it will be negligible... it hasn't even had a chance to build up heat from sustained frictional contact, which really starts to drop performance. However, using an engine how it's intended, that small percentage of energy loss acummulates into something substantial over time. Basically, drops in a bucket that you keep using... eventually you've got enough water retained to bother mentioning.

All this talk about friction - unnecessary.

Let's say you have barrel A and B again, both made of high friction rubber this time...

If you use enough propellant (maybe an explosion in this case) such that you can keep it accelerating throughout the length of each barrel... the longer barrel will have a higher velocity using the same amount of propellant. The fact there's WAY more friction involved in this situation... does not matter. The bottom line is that the friction is not substantial enough to result in 0 acceleration or deceleration.

This is the case with 8-10" barrels vs. shorter barrels.

[RRfireblade]

Originally posted by Miscue


Cuz I said so. ;)

Two-piece barrels typically have 5-6 inch control bores... the tip is not "effective" barrel. One piece barrel has longer effective barrel length.

I guess you don't read very well.What I said was subjective is the fact that "most" one piece barrels are ported at somewhere around 1/2 of the total length.Except where I noted and maybe some others,a typically ported 1 piece is nearly equal to a 2 piece in effective length.Thus the Only remaining difference in efficiency comes from the friction left in the one piece how ever small that might be.

Jay.

[RRfireblade]

Originally posted by Miscue

I agree, friction "matters." However, the energy lost due to friction from barrel/ball contact is very small in comparison to what is put into propelling the ball.

Hold a barrel vertically, and put a ball in it. If the ball falls through, the deceleration on the ball caused by friction from barrel contact is less than 9.8 m/s^2, the approx. pull of gravity at standard ATM. Use a barrel that fits the ball just enough to keep it from falling, and the deceleration is around 9.8 m/s^2. Use a barrel that's very tight, and the deceleration will be above 9.8 m/s^2.

How can you assume the rate of deceleration of a ball not capable of being pulled through the barrel by gravity?
In my own 3 min backyard test,I switched inserts on a freak from almost loose to so tight I though it would break in the barrel and saw + or - 30-40 fps.I'm not sure I would call that negligable.

Jay.

[MarkM]

Miscue, 1st my bad example of using the SAME two letters as you already had :rolleyes: Barrel B is a more inefficient barrel due to the friction...yes that word again.

2nd Gas flow technology irrelevent within the paintball world...mmmm well unless the mechanics of gases within a non expanding state have changed...thats what the exhaust manifold on an ICE is, so all those muscle cars owners and souped up rice burners owners are wasting their money ??

3rd keeping this within the boundarys of general understanding will keep this thread in paintball talk...didn't read the last line of my post?

4th As you couldn't have read the last line in my last post..http://www.automags.org/forums/showthread.php?s=&threadid=68567

Honest, just trying to keep this civil :D

[nerobro]

Originally posted by AutomagBoy
sooo, whats more accurate one piece or two? This should be moved to deep blue.

Neither. that's the simple answer. As long as both launch balls with no spin the balls will be equally accurate.

In theroy a single bore will be more accurate over a wider range of paint. With the larger bore out front you're more likely to get the skip-skip from the sides of the barrel and set that ball spinning heavily.

[Automaggin2]

I dont feel like reading through the whole post, my theroy was probably around said but here it goes

I think 1 piece barrels are beter then 2 piece barrels. In some 2 piece barrels, the back of the barrel is less then 6 inches long, and as you know, the first 6 inches of the barrel is what gets the ball up to speed. No say the back is like 4 inches long, and its stepped bore, like most 2 piece barrels. You should your gun, the ball flows through the first 4 inches, then when it gets to the step, the ball doesnt make a complete seal around the barrel, allowing air to escape around the ball, causing the ball to wobble and for hte gun to use more gas.

[AutomagBoy]

someone should get two of the same barrel except one is two peice and one is one peice and do an accuracy test.

[TippmannMan]

ok im not going to even begin to debate the physics of one vs two piece barrels but does it really matter? its not like the more accurate of the barrels is going to be DRASTICALLY different. a $30 custom products with a good paint match is good enough for me.

[Marek]

Originally posted by joeyjoe367
If it were up to me, I'd have a 1 pc CP barrel for every bore size, and every length.

I agree. I would love to have 5 more CP barrels (I have a CP 1 piece alum. .689) of varying bore sizes at 14 in. Now, just to find a place that sells them with a size other than .689.