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    Airsoft Precision Barrels

    Post  Guest on 25.01.10 22:12

    So I was in the barracks today helping out my friend get into airsoft. His roomate works at AirSoftAtlanta, so I figured he would be helpful as well. I told my friend that he should look into lengthening his barrel and getting a TBB. The Airsoft Atlanta employee looked at me like I was an idiot and said "wow honestly a longer barrel? Go ahead and throw your money away" After a slight discussion we continued, and I said to get a Prommy 6.03. He once again scoffed at that, stating that 6.03 barrels will do nothing for your accuracy, and that Prometheus barrels are just a bad brand. He told me that his 4 inch 6.01 barrel would beat a 500mm prommy 6.03. I told him if he would prove it I would believe it and until then I'd stick to whats always worked for me. So my question is, whats the consensus on barrel diameter and barrel length? Effects? Proof?
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    Electioneer

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    Re: Airsoft Precision Barrels

    Post  Electioneer on 25.01.10 22:38

    This Airsoft Atlanta employee obviously knows nothing. A longer barrel will help. The tighter a barrel is that means more FPS but not necessarily more accuracy.

    Prometheus makes great barrels by the way.


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    #CW!!ZERO

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    Re: Airsoft Precision Barrels

    Post  #CW!!ZERO on 25.01.10 22:41

    I know that when I polished my 6.08 barrel i got far better results then my same length barrel that was 6.01, polished and unpolished. As for length, it is almost like a match up for fps. If the barrel is long then a gun will have to shoot faster to keep accuracy. With bobby old m15 he had the long barrel version but it only went about 315fps, when he switched to my shorter m4 barrel it was much more accurate. Also with my Vsr-10, the stock g-spec barrel was more accurate for fps below 400, but when i went higher then that my 455mm barrel was more accurate. So pretty much there is a right barrel length for every fps range.


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    Airsoftguy238

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    Re: Airsoft Precision Barrels

    Post  Airsoftguy238 on 25.01.10 22:44

    Ive got tbbs in most of my guns and i love them. I honestly find most AA guys dont have much experience with what there talking about
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    Rhino

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    Re: Airsoft Precision Barrels

    Post  Rhino on 25.01.10 22:45

    I will not get in to great details on this but I can say that the barrel length must be matched to the cylinder also. You just can throw in a long barrel then the cylinder was designed to have.


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    Re: Airsoft Precision Barrels

    Post  Admin on 25.01.10 22:54

    Aggressor wrote:works at AirSoftAtlanta
    There's your problem. I've had people that work at AA tell me that KWA pistons are different than the TM standard and won't fit other guns (even though I have had a KWA piston in my TM SOC16 for about 20k rounds with no problems), I've had an AA employee try to sell me an Angel HighSpeed piston (has three fewer teeth) for a DMR build, stating, "No, it'll work, it's from Japan", and I've had AA employees sell my friend bore-up VSR-10 parts and swearing to him he didn't need a bore-up VSR-10 receiver. I've had an AA employee SWEAR to me that a RealSword folding stock wouldn't fit my Echo 1 AK (BTW - fit just fine).

    As for the effects of barrel diameter, check out Russel's old tightbore thread.

    Here's a post from ASF (pre-Sheeple lol)

    My major in college is aerospace engineering, and I've taken more mathematics and physics courses than I'd like too. So here is a brief analysis to verify that a longer barrel inherently creates a more accurate gun than a shorter one. Even though everyone knows this for real-steel, and virtually anything that launches a projectile.

    Projectile: an object that moves in two dimensions under the influence of only the gravitational force.
    (Physics: For Scientists & Engineers, by Randall D. Knight)

    Vfx = Vix * Cos(Theta)
    Vfy = Viy * Sin(Theta)

    Where Vfx and Vix, are final and initial velocities in the horizontal direction. And where Vfy and Vix are final and intial velocities in the vertical direction.

    If the projectile is first propelled through a barrel, then the vertical velocity is virtually zero. I say virtually because there is a small deviation within the barrel and bb. If there is no deviation between the two surfaces then the friction is too high for impending motion, where a force applied is larger than the static friction within the barrel. Once the projectile is in motion, there are two frictional forces acting on the projectile.

    1. Friction due to barrel: There is kinetic friction on the bb as it moves through the barrel. Which is determined by the equation F = uX. Where u is the coefficent of friction for the barrel and bb, and X is the distance of the barrel.

    2. Friction due to air: Any object that moves through air has some characteristic of air resistance, this is complicated, as it is dependent on the surface area of the object, mass, or density, and also velocity. The general equation is D = -Bv, where B is the damping constant, as long narrow objects have lesser damping constant than that of flat objects, v is the velocity, and D is the drag force.

    In general, if we treat the bb as a particle, and apply particle physics, igonoring rigid body physics, and if we ignore friction, then the only force acting on the object is gravity, along with the disapating force of the piston that thrusts the bb out of the barrel.

    The barrel will contain the projectile, and keep it's motion within a horizontal direction, thus only a horizontal velocity.

    Looking back at the equation, since the sine of zero is zero, and the cosine of zero is one with respect to the angle between the barrel and bb which is parrallel, which is zero. Thus even if there was a intial vertical velocity, sine of zero is zero, meaning the resulting final vertical velocity is also zero. This is due to the barrel impeding the motion of the bb in a vertical direction. Meanwhile, the horizontal velocity is at a maximum, as cosine of zero is 1, meaning that initial horizontal velocity is equal to the final horizontal velocity.

    The equation for this velocity is shown by the energy equation.

    KE = (1/2)*m*V*V

    Unforunately I am not able to write velocity squared so I improvised and just multipled it twice by V, which is the initial velocity, and also muzzle velocity. Where m, is the mass of the bb, make sure that is in kilograms, and KE is the energy. So if you know the joule of your spring within your gun, solve backwards, then you get your muzzle velocity.

    However, once the bb leaves the barrel, then the barrel no longer impedes movement in the vertical direction, and the bb due to Bernoulli's principle of fluid dynamics the projectile now will have lift, causing it to rise to a certain degree, depending on velocity. Hop up places a spin on the projectile to help maximize the idea of lower and higher air pressures created by the surface of area of the bb to maximize the distance the bb travels.

    Because the bb now can move in a vertical direction, then it is no longer moving only in a horizontal direction alone.

    Thus, a longer barrel helps keeps the projectile moving in a horiztonal direction. There is probably some time function equation, that relates how long a projectile must stay within a barrel to dispate the vertical initial velocity/ force on the object created by the piston. But, the longer the barrel, the more time it it allows for the dispation of that vertical velocity, because real world wise, there is friction, and air resistance, along with that small deviation between the barrel and bb that causes that vertical intial velocity. Therefore the longer barrel equals better accuracy, with airsoft or real-steel, whereas the shorter barrel equates to lesser accuracy.

    Hopes that helps to settle the myth, but you don't have to take physics or math to understand this, just look at real-steel, you don't see short and stubby sniper rifles.

    And there is a whole other set of equations that help snipers determine distance, and drop of there round, all formulated by the weapon they are using, the distance they want to place the shot, and the round they are using. But I won't go in great detail with that because it is finally Christmas over here and I don't have time.



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    Re: Airsoft Precision Barrels

    Post  hurley on 04.02.10 13:19

    Hi guys. My name is Brandon and I work at Airsoft Atlanta. I would just like to respond to what I believe are some misconceptions about tight bore barrels as well as a few comments regarding our customer service.

    First of all, I am never rude to customers. I have talked several people out of buying tightbore barrels, but I have never tried to make anyone feel stupid or sheepish in the process. There is a tremendous amount to learn about airsoft when getting into it, and I try my best to explain things in a way people can understand and to help them maximize their gain for the money they spend here. This is my definition of good customer service.

    I do have quite a bit of experience playing and working on airsoft guns. I have tried nearly every combination of barrel, piston, spring, and BB, and chronographed them all, and done empirical range tests, not to mention that I have been an airsoft tech for years and repaired or upgraded 100's of gear boxes. Here is what I know from my experience installing and testing tight bore barrels. First of all, the cost:benefit ratio is terrible. If your goal with a tight bore barrel is increased FPS, then yes, they usually do give a slight boost in FPS. Is that small boost (usually 10-15FPS) worth the $70-$130? That's for you to decide, but I don't think so. Also, if your gun has a very good air seal, then messing with that by installing a tight bore can often result in a DECREASE in FPS.

    If your goal with a tight bore barrel is increased accuracy, then you're really barking up the wrong tree. I have seen no increases in accuracy from the use of a tight bore barrel. In fact, using a tight bore barrel can make your gun much more sensitive to tiny flaws in BBs, DECREASING your accuracy (this is especially true for 6.01mm and smaller barrels). The biggest increase in accuracy can be achieved from utilizing heavier BBs, and a better hopup system. There is considerable debate about what is the best hopup, but I find a stock hopup with an H-bucking works pretty stinkin well.

    Longer Barrels: I'm assuming that you guys are like me, and you want the best damned gun on the field. If that is the case, then here's why you want the shortest barrel possible for your gun. There is a very limited volume of air in the cylinder. In a real gun or gas rifle, there is an enormous amount of gas propelling the projectile, so having a longer barrel usually means an increase in FPS, but due to the small volume of air in an AEG cylinder, this is usually not the case. The chrono standard at almost all fields is to use .20g BBs. These .2g bbs actually leave a shorter barrel (that is paired with a full/zero cylinder) before they absorb the maximum amount of energy from the piston. However, the heavier .25 and .3g bbs will absorb more energy because they stay in the barrel a little bit longer (due to their increased inertia & density).

    Empirical Data: My G36c (stock barrel, full cylinder) shoots .2g BBs at an average of 405FPS, giving them a muzzle energy of 1.52J. But, I shoot .3g BBs, which chrono at 365 FPS, giving them a muzzle energy of 1.86J. When I had a 509mm Barrel in my gun, yes, my .2g shot faster, but my .3g did not. They stayed at around 365-370 fps.

    All of this is to say, if you want a tight bore barrel, by all means, go for it, but I would be doing our customers a disservice if I did not try to inform them about some facts about tight bore and longer barrels. I pretty strongly believe investing in more magazines, better BBs, better batteries, and a better hopup / nub is a much better investment, especially if you have done relatively little to your stock gun, already.
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    Shmekal

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    Re: Airsoft Precision Barrels

    Post  Shmekal on 04.02.10 20:57

    honeslty when you start getting longer barrels that requires more mech box work because with a longer barrel you have to have a better airseal if he wants range get a g&p hop unit with a standard m4 barrel assuming that is what he has dont get a tight bore and get a firefly soft bucking if it is shooting under 400 and a hard bucking if it is shooting harder that 400
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    reconsniperga

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    Re: Airsoft Precision Barrels

    Post  reconsniperga on 04.02.10 22:18

    You guys are rediculous. I believe the topic reads "Airsoft Precision Barrels" not "Airsoft Atlanta is teh win or teh fail"


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