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TK hop twist barrels, are they worth it?


my_plague_666

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hey folks. how exactly are you meant to use these barrels, the name implies that you use them in conjunction with conventional hop up, but that doesnt sound right at all.

 

do these barrels really offer much in the way of range and accuracy that a good tightbore and hop rubber cant?

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the hop twist term is just the name they picked for this product. by the way they say it works, it actually doesn't have anything to do with 'twisting'.

as you probably noticed, the barrel presents twisted indentations, and not protrusions, like a normal weapon barrel. those are supposed to channel the airflow around the bb and hopefully make it slide down the barrel without touching the sides.

that won't affect the hop effect, actually if it all goes like theory, it will rather help it, by making the bb keep the initial hop effect and not losing it by touching the barrel.

you'll find a very nice film

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the hop twist term is just the name they picked for this product. by the way they say it works, it actually doesn't have anything to do with 'twisting'.

as you probably noticed, the barrel presents twisted indentations, and not protrusions, like a normal weapon barrel. those are supposed to channel the airflow around the bb and hopefully make it slide down the barrel without touching the sides.

that won't affect the hop effect, actually if it all goes like theory, it will rather help it, by making the bb keep the initial hop effect and not losing it by touching the barrel.

you'll find a very nice film

 

The results from the video are certainly interesting.

 

I wonder what his groupings at 20 and 30 meters would have looked like. How would the TK twist barrel compare against a 6.03 tightbore or a DB Custom 6.01?

 

If anyone else has performed these tests, it'd be great to know what your results were. :)

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I havent performed the tests but ive used pretty much all the different makes of Barrels.

 

I really like the TK barrels but i was never sure if they were just a very high quality 6.04mm tightbore or something more.

 

They give good performance but honestly, once you get into the realm of tightbores its more about material of the barrel and your hopup rubber/unit than anything else.

 

I really never noticed any huge accuracy differences between kobas, km's, prometheus, madbulls etc.

 

The bottom line is that whether or not the vortex feature works, the barrel is still an extremely well made 6.04mm tightbore so you cant go wrong with it unless you believe you need a tighter bore diameter.

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I havent performed the tests but ive used pretty much all the different makes of Barrels.

 

I really like the TK barrels but i was never sure if they were just a very high quality 6.04mm tightbore or something more.

 

They give good performance but honestly, once you get into the realm of tightbores its more about material of the barrel and your hopup rubber/unit than anything else.

 

I really never noticed any huge accuracy differences between kobas, km's, prometheus, madbulls etc.

 

The bottom line is that whether or not the vortex feature works, the barrel is still an extremely well made 6.04mm tightbore so you cant go wrong with it unless you believe you need a tighter bore diameter.

 

Hmmm...

 

I should buy one of each for my SL9SD project gun and conduct the tests myself. Thank goodness my toy budget allows for it.

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I compared a TK barrel to the Prometheus barrel in my SG1. The Prometheus barrel would score 2" groupings at 25m. The TK barrel would hit 2 or 3 shots within an inch of each other then the next shot would, literally, be off the target.

 

I've also had a play with a KSC G17 fitted with a TK barrel. This was interesting because I have a KCS G17 fitted with a few upgrades (but with a standard barrel) so it shoots very nicely.

The TK gun was shooting around 300fps. My gun shoots at 315fps. Both guns had the hop set so they shot a flat trajectory and the TK gun DID seem to have a greater range than mine. Basically, we were just shooting at each other and moving further apart. After about 30m I was having to lob shots upwards and into the wind whereas the other gun seemed to remain pointed straight at me and the BBs still hit me.

 

This is pure speculation but I wonder if the TK barrel works better in a GBB because of the way the sudden blast of pressurised air has the BB out of the barrel so quickly?

 

I mean, assuming the vortex-thing DOES have some effect, I reckon the pressurised air can suspend the BB in the middle of a pistol barrel while it travels 10cm, to the muzzle. Job done.

By contrast, in an AEG, the barrel is much longer and there's more opportunity for the pressure to equalise around the BB and for the hop-up to spin the BB up toward the top of the barrel.

If this IS the case, it'd explain the varying results I saw with the SG1.

I suspect, if the BB can travel all along the barrel while maintaining its little vortex-thing, then the shot is accurate whereas, if the vortex collapses (and the BB hits a groove in the side of the barrel) you get a flyer.

 

I keep labouring this point but I prize consistency above ultimate accuracy in a gun. I'd rather KNOW I was going to hit a 6" wide area 100% of the time than think I might hit a 2" area 60% of the time.

For that reason I'd have to go with a normal tightbore rather than a TK barrel in a rifle. I'd probably go for a TK barrel in a pistol though.

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I've never bought the "bb suspension" idea. A BB will leave the hop bouncing in the barrel, and Bernoulli tells us that pressure where air slips past the BB will be lower, thus causing...more bouncing. A little air riding the rifling around the BB won't prevent more air from slipping past somewhere else, creating pressure drag.

 

The rifling isn't going to produce any vorticity in the sense that most people think it will, either. It guarantees turbulent flow along the barrel, reducing viscous drag, but you don't get any macro scale, tornado like twists of air down the barrel or following the BB.

 

They're a nicely finished, well toleranced barrel. I think any performance gain over a stock barrel comes from that fact along.

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I compared a TK barrel to the Prometheus barrel in my SG1. The Prometheus barrel would score 2" groupings at 25m. The TK barrel would hit 2 or 3 shots within an inch of each other then the next shot would, literally, be off the target.

 

I've also had a play with a KSC G17 fitted with a TK barrel. This was interesting because I have a KCS G17 fitted with a few upgrades (but with a standard barrel) so it shoots very nicely.

The TK gun was shooting around 300fps. My gun shoots at 315fps. Both guns had the hop set so they shot a flat trajectory and the TK gun DID seem to have a greater range than mine. Basically, we were just shooting at each other and moving further apart. After about 30m I was having to lob shots upwards and into the wind whereas the other gun seemed to remain pointed straight at me and the BBs still hit me.

 

This is pure speculation but I wonder if the TK barrel works better in a GBB because of the way the sudden blast of pressurised air has the BB out of the barrel so quickly?

 

I mean, assuming the vortex-thing DOES have some effect, I reckon the pressurised air can suspend the BB in the middle of a pistol barrel while it travels 10cm, to the muzzle. Job done.

By contrast, in an AEG, the barrel is much longer and there's more opportunity for the pressure to equalise around the BB and for the hop-up to spin the BB up toward the top of the barrel.

If this IS the case, it'd explain the varying results I saw with the SG1.

I suspect, if the BB can travel all along the barrel while maintaining its little vortex-thing, then the shot is accurate whereas, if the vortex collapses (and the BB hits a groove in the side of the barrel) you get a flyer.

 

I keep labouring this point but I prize consistency above ultimate accuracy in a gun. I'd rather KNOW I was going to hit a 6" wide area 100% of the time than think I might hit a 2" area 60% of the time.

For that reason I'd have to go with a normal tightbore rather than a TK barrel in a rifle. I'd probably go for a TK barrel in a pistol though.

 

First, apologies to the my_plague_666 for sortof-jacking the thread. :unsure:

 

Stealth - Your conclusion is interesting and seems logical. Thinking about your results, I can easily imagine a long barrel cancelling any gain in flight stability initially imparted by the air bearing-like effect from the twist. You would have to significantly maintain the same or similar air pressure for much of the entire length of the barrel.

 

So basically, from what you found, TK appears works great in the short barrel of a handgun but is not so lovely for a long-barreled rifle.

 

I changed my mind.

 

I want to see how it does in my P90.

 

:D

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So basically, from what you found, TK appears works great in the short barrel of a handgun but is not so lovely for a long-barreled rifle.

 

I changed my mind.

 

I want to see how it does in my P90.

 

:D

Well, I gotta say that my proper dealings with TK barrels has been limited to my SG1 barrel and to the play I had with the G17 c/w a TK barrel. I couldn't comment on how it works with other barrels.

 

The only fly in the ointment, according to my little theory, is that TK recommends that the twist barrel is only used with guns up to about 1J.

If my theory is correct then you'd think the effect would improve as the power level increases.

 

I dunno.

TBH, the engineer in me agrees with Glenn. I have trouble believing that a barrel that costs less than a good quality tight-bore can be manufactured accurately enough to create a stable vortex inside the barrel which allows the BB to float up the middle of it.

Bear in mind, for example, that the air travelling around the BB would need to be travelling at exactly the same speed at all points or the BB would move off-centre one way or another.

 

However, there are times when air can do strange things. It might be possible that, at low levels of power the air bypassing the BB is sort of self-regulating in some way. Wouldn't like to guess how but it's possible, I suppose.

This might explain why they're only good for power up to around 1J.

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I've put one in my mp5 and i have to say accuracy seems to have gone up from stock but more importantly was the consistency of the bb when chrono'd. I have an m100 spring in it and it would shoot at 350ish +- 5 fps with the stock barrel stock hop bucking. When i put in the 1J spring with the hop-twist and soft firefly hop bucking it was shooting at 290. I wasn't happy about that so i tried putting in the M100 spring back in...nd it shot at 315. I assumed it was lower because of the air passing by the bb to keep it "centered" in the barrel. I tuned it to shoot at 328 and what surprised me was how consistent the chrono test was. I shot 328.4 fps exactly 3 times in semi. After that i shot a 328.5 and it went back to 328.4. I've NEVER seen it do that before so i was shocked at how consistent it was with the fps. I never did a paper target test for accuracy or consistency but when I was dialing the hop-up for a skirmish this past sunday i would hit a soda can about 50ft with iron sights. I know that's not very far but i could hit it with EVERY SHOT. MP5 barrels are only 229mm in length and i'm running a low fps so I think tanio koba's suggestion of keeping it 1J or less might be something worth following.

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I think it is all wrong to compare a stock inner with a TK barrel like on the video.

 

Take a 6.04 prometheus or other and compare that to TK barrel.. Then adjust the FPS for each test so that both the 6.04 other type and TK barrel have same fps when testing.

 

If you put a Prometheus 6.04 and have good range and grouping with 300fps.. Then you can`t just drop in the TK barrel and compare when that might drop your fps to 250fps.

 

If your limit for the field or country got 300fps on auto, then you should offcourse have 300fps when using the TK. So maybe the TK would be even better when upping the fps.

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well, heres my situation, i'm looking at one of these for a support gun as im sure someone somewhere said that his twist barrel keeps BBs in flight much longer, allowing much better range (even if it has lost most of it's energy).

 

are these claims true? because if i can achieve a good bit of extra range and keep reasonably tight groupings i'd be a happy man.

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well, heres my situation, i'm looking at one of these for a support gun as im sure someone somewhere said that his twist barrel keeps BBs in flight much longer, allowing much better range (even if it has lost most of it's energy).

 

are these claims true? because if i can achieve a good bit of extra range and keep reasonably tight groupings i'd be a happy man.

 

 

Total and absolute BS.

 

Before asking why TK barrels don't help...ask why the would. Much shorter answer.

 

They don't contribute any energy or aero effect to the BB. Once is leaves the confines of the barrel, its just rotating and translating like any other BB.

 

 

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FWIW, on the assumption that the whole vortex-thing does work and keeps the BB away from the walls of the barrel, it's possible that the TK barrel gives more range by reducing the amount of backspin that's lost to friction as the BB travels along the barrel.

 

I'm not sure I actually buy this cos, IMO, you have a couple of quantifiable absolutes when shooting a gun.

1) The muzzle velocity.

2) The amount of hop-up.

 

The velocity is, obviously, quantifiable with a chrono.

The amount of hop-up IS quantifiable since, regardless of how it's applied, the hop needs to be enough to make the BB fly horizontally for as long as possible.

 

If you're firing a BB out of a smooth-bore barrel at 300fps with the BB flys horizontally, and then do the same thing with with a TK barrel (same fps and same trajectory), I honestly can't see any other factor that, further down-range, would cause the BB to fly further.

 

The FPS is the same so both BBs will be affected by gravity at the same rate.

This means that, if the BB is gonna travel further from the TK barrel, it's GOT to be the amount of hop-up that causes it.

However, if the same kind of BB is flying horizontally from the muzzle of a smooth barrel and a TK barrel then the BB must be spinning at the same rate (cos, if it wasn't, it wouldn't be travelling horizontally, it'd be rising or falling) so you'd think it would slow down at the same rate and the range would be the same.

 

Or, in summary, for the TK barrel to increase the range of a gun it must provide some way for the BB to maintain a stable rate of backspin for a longer period.

Possible?

You decide. :unsure:

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Take a 6.04 prometheus or other and compare that to TK barrel.. Then adjust the FPS for each test so that both the 6.04 other type and TK barrel have same fps when testing.

 

If you put a Prometheus 6.04 and have good range and grouping with 300fps.. Then you can`t just drop in the TK barrel and compare when that might drop your fps to 250fps.

That's probably the reason why there haven't been a credible "test result" saying "x tightbore compared to the TK is..." since the same pressure of air pushing a bb out of the two barrels will result in a different FPS so it's hard to come to any conclusion. The technology in the way a tk barrel works just too different from how normal tighbore barrels work. To me it's just another tightbore barrel option.

 

Before asking why TK barrels don't help...ask why the would. Much shorter answer.

 

They don't contribute any energy or aero effect to the BB. Once is leaves the confines of the barrel, its just rotating and translating like any other BB.

But the idea of the tk barrel is that the bb leaves the barrel w/o having contact with the barrel itself and may help with a straighter path. I personally prefer PDI's 6.05 barrels over anything else for a good balance between range/accuracy on a higher fps gun.

 

 

To the original poster, basically it's up to you. Some people like it, some people don't. You know the theory behind the twist of the barrel now and it's your choice. There have been claims that it works only with low fps guns. If you're planning on shooting with a higher fps then i'd suggest going with a normal (but high quality) tightbore barrel and a better hop up system (either bucking or nub) to get your range/accuracy up.

 

--stuff he said--

Maybe that's what it really does...just aplifies the effect of the hop on the bb and that may be why people "seem" to be getting greater distances with the hop-twist. People would get distances out of their gun by putting in a higher spring rate to "push" the bb further and that makes physical sense so maybe a higher fps would negate the effect of the "twisting" air cushion for the bb cuz it's no longer relying on the rotation to keep it afloat but the pressure of the air behind it. hmm...hmmm...i dunno...i have a headache now. :)

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Found it!

 

Well, at least one of the texts that I came across when researching into TK Twist last year.

 

Words out of the very mouth of the designer, a guy who is one of the Godfathers of airsoft: Tanio Kobayashi

 

1. Please explain how your Tanio Koba Twist barrels function. There is a lot of confusion in the United States to how a rifled barrel works with hop-up. How does this system improve the range of the BB and why is it's performance linked to the velocity of the BB.

 

Koba: "Since the BB is underpowered, its muzzle velocity declines if it touches to the inner surface of the barrel. Therefore, you cannot let BB touch to the surfaces of the inner barrel while inside it. But you cannot expect any effect from grooving (the “twists” inside the Tanio Koba Twist Inner Barrel) with that method. On the other hand, hop up rubber can make BB spin to up and down and run inside of smooth barrel in gentle straight zigzag course. This zigzag point of contact is affected by some variety of conditions like shape of BB or side gap of contact point with the hop up rubber. It changes each shot just little bit and there is a limit as long as there is a clearance of BB and inner barrel.

 

With this hop up effect, I made small difference in level with minimum air loss and make this difference in level as a zigzag contact point. This difference in level gives the regular direction bias to BB and the air current in the middle of the groove leads BB to the second contact point. BB doesn’t move straight precisely like a spinning trajectory, but just makes a regular bias trajectory making regular zigzag movement. In this fashion it keeps regular trajectory effect with the balance of hop up rubber. Therefore, it improves grouping quality, but it doesn’t improve the range and the muzzle velocity in comparison with the normal hop up barrel.

 

After all, the theory of so-called KOBA Twist Barrel is just something like a trick of “KOBA magic!” as written in PR or instructions. Even so, it became very popular in the world. I myself got surprised! I’m very glad about it."

 

See this and the rest here: http://www.renegaderecon.com/kobascorner3.php

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That's probably the reason why there haven't been a credible "test result" saying "x tightbore compared to the TK is..." since the same pressure of air pushing a bb out of the two barrels will result in a different FPS so it's hard to come to any conclusion.

It baffles me why people keep saying "but it's no good just replacing a tightbore with a TK barrel cos....."

 

I don't mean to bang my own drum but that is EXACTLY what I did. I built my SG1 so it shot at exactly 330fps (with the Prom' 6.03 barrel). A mate asked me to build an identical gun and I took the opportunity to fit it with a TK barrel in it. Both guns used an M100 spring and the spring guide was shimmed so both guns were firing at the same 330fps.

 

The results I got, after testing both guns, were what I said above. Basically, the TK gun would shoot a couple of accurate shots and then, just when you started to think it was doing the job, it'd fire a BB so wild it didn't even hit the target.

 

gah. so many mixed reports and ideas. as far as i can see from this the whole concept seems largely based on theory, maybe i'd be better off just using a bog standard nice quality tightbore rather than fancy new ideas.

 

thanks for the help folks :)

Indeed.

 

I gotta say, from my experience of the TK barrel, you'd get a column of BBs whizzing toward the opposition with roughly 1/3rd of them scattering off to the sides as well.

 

Course, in a support weapon, that might actually be desirable. :unsure:

 

Words out of the very mouth of the designer, a guy who is one of the Godfathers of airsoft: Tanio Kobayashi

See this and the rest here: http://www.renegaderecon.com/kobascorner3.php

Ah yes. "Koba magic".

 

Glad we sorted that out then. :rolleyes:

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I gotta say, from my experience of the TK barrel, you'd get a column of BBs whizzing toward the opposition with roughly 1/3rd of them scattering off to the sides as well.

 

Course, in a support weapon, that might actually be desirable. :unsure:

 

yeah i wondered that too. but i'll be using mainly mids (madness, i know, but fun) and a hicap or two for when the s**t hits the fan, so i'll ideally be wanting the BBs to hit the mark quite accurately as i wont be able to use the old 'if i hold down the trigger until my battery dies, i must hit someone' routine used by some.

 

i'm undecided what to do about groupings etc, but my self imposed ammo limitations are making me think that accuracy may be better than spread, support role or not.

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I had the same experience with my tk as stealth did. Mines in the star l85 and is doing about 340ish. I get about 3 or 4 shots on target and then one goes off at an angle that looks like it hit the flash hider its so steep.

 

Personally i wouldnt recommend one tbh.

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Was wondering...how would these barrels be affected by movement compared to a standard TB? I mean in a perfect enviorment you're completely motionless & shooting at a motionless target, but in the real world you're shooting at someone who's usually ducking for cover & returning fire.

 

how much movement would it take to overcome the "air cushion" *snigger* & cause the bb to slam into the walls of the barrel anyway? I wouldn't think it would take much considering the fps & would assume that it would cause worse performance for a TK barrel than a TB. Also the longer the barrel the smaller the shooter's movement needed to negatively affect it right?

 

Just rambling outloud.

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Ive used these barrels in 363mm's 300mm's and mp5 length and ive never had any problems with inconsistencies.

 

Ive always thought they were rather nice tightbores whether or not the "hop twist" feature worked.

 

The only way you're really going to figure out if you'd like one is to give it a try.

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Wow, if this isnt the nth time this question has come up.

 

I think everytime we end up saying its inconclusive, but results are more profound in gas pistols

 

After seeing what a 6.01 DBC Tightbore does, i wouldnt put in a TK Twist if you bought it for me.

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