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Skyi///

Tanio Koba Twist Rifled Barrels

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I was talking to my Mechanical Engineering Professor about making barrels, and he said that it would require a reamer that they don't have or have the money to buy

 

So I won't be custom fabricating barrels anytime soon :(

 

The department head needs to pay attention next time he says that they can manufacture any part you could imagine

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so I'm looking into an anomaly in the barrel at the moment. The barrel has rifling which spins the air (we know this). Guns that shoot at higher fps push air through the barrel to fast for the grooves to be affective. What I'm looking into is the cylinder volume to barrel length OF TK BARRELS. When a full cylinder is put into a TK barrel the piston does not speed up as fast and accelerates the bb slower than if it had time to accelerate before compressing the air in the cylinder. I found this out when testing my roomate's P90 which has an M120 in it and a full unported cylinder. The accuracy was very impressive. There was another player in our local club ,who I got hooked on the TK, who put an M110 into his MP5, and it was shooting 365fps. His accuracy was total crap with .2 gram bbs (even worse than stock barrel), but when he put .28's into his gun it was phenomenal. There are two different factors that I believe are present.

 

1. The increased air volume of the full cylinder slowed the acceleration of the BB enough for the tornado effect to kick in EVEN AT HIGHER FPS.

2. The increased weight of the bb DID in fact affect the acceleration of the bb and give the tornado enough time to kick in.

 

I know I've been telling people all along that increasing bb weight to get the fps down to 328 is hogwash. I'm not so sure now. I'll keep testing this and come up with some numbers.

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It makes sense then that you'll need a higher twist rate for a twist barrel to work on hotter guns, no?

 

It may be possible to make your your own twist barrel. You'll need to cut helical grooves on a mandrel with a minor diameter of say 6.02mm and the major diameter will depend how deep you want the groove to be. Insert the mandrel into your custom barrel which has an ID slightly larger than your mandrel major diamter/OD and "autofrettage" it by housing the custom barrel in a rigid hole. Proceed to compess both ends of your custom barrel by means of hydraulic assistance and voila, you have a twist barrel. Remove the mandrel by unscrewing it from the custom barrel.

 

Lol if anyone really tries this out let me know.

 

I also think you'll probably need some serious porting to increase accuracy since you're introducing excessive blow-by.

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It makes sense then that you'll need a higher twist rate for a twist barrel to work on hotter guns, no?

 

 

I also think you'll probably need some serious porting to increase accuracy since you're introducing excessive blow-by.

 

Yes. I was thinking about that and realized that I cannot cut a new barrel with the tools I have. It should work like that though. What I'm looking at is kind of a band aid for higher fps setups and regular TK barrels. The thing is if you push air through the barrel very fast (high fps) then the grooves don't have enough time to catch the air and spin it. If you use a non ported cylinder on a TK barrel you have several things happen. First and most interesting is that the piston does not accelerate before air starts to build up pressure behind the bb. Normally with a ported cylinder the piston had the area behind the edge of the port to accelerate giving the bb an initial push. The bb accelerates as the piston continues on to the cylinder head. For a high fps gun the initial push is to fast for the rifling to start to affect it and the inconsistencies caused by the rifling and pressure give inaccuracy. With a full cylinder the piston does not have time to make an initial push. It starts from 0 and builds to X. Because of this I think the rifling will have time to catch the air coming out of the cylinder and put it into a stable spin before it can get out of hand. The big thing is the time it takes for the rifling to get the cyclone affect. I'm not sure how far I can push it yet. With higher springs I expect the piston to be accelerating out the door at a higher than acceptable velocity.

That was the first thing that you get from the non ported cylinder. The second is exactly your second point. You get excess air. The excess air ensures that the extra barrel volume is created by the grooves is filled and if the barrel is working properly it should continue past the barrel until it dissipates. Normally excess air would cause some turbulence but since we've put it into a spiral it shouldn't break down the same way. It should have laminar flow for a few extra milliseconds than would regular airflow through a regular airsoft barrel.

Edited by Grady the Scot

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Quick question: Does it matter what length your tk barrel is? Or does it need to match the stock barrel? Currently I have a sp110 and a #14 oring. Now I've found a 500mm tk for a decent price and I'm wondering if the length will affect the the airflow/rifling.

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I'm in the process of upgrading my TM VSR G-Spec. At the moment it's clocking at about 370 fps after upgrading the spring. I decided to wear out the stock internals before replacing them because I'm on a tight budget. Now this has happened I'm looking to replace all the internals with all Laylax parts which should bring me up to my 400 fps site limit.

 

Now the last time I looked I couldn't really find any info on the TK twist barrels, but since the last time I've looked it seems a lot more people have used them and like them. So I'm wondering as my site has quite a low fps limit on sniper and support weapons (400 fps) would I be better off down grading the spring and putting in a VSR TK twist barrel? Obviously I'd have to carefully drill out the barrel cap / silencer mount on the G-Spec so I could feed the 430mm barrel thought and then hide it with the silencer.

 

I also still plan to replace the internals with laylax parts as at the moment the tiger sear has worn; so I can't :censored2: the rifle as the bolt just slams forwards again without priming the spring. I still have the original TM spring, but do I want to use that or go for something just a little more powerful like an M100 or 110?

Edited by Mad Jim

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I have one of these barrels, and have it installed in a VSR-10. I've spent a bit of time and money on upgrades, and unfortunately feel like the gun shot better before I opened it up. I will say that now If I shoot 20 rounds at 80 feet the target shows 3 different 2 1/2 groups. 1 at POA. that contains 60% of the shots, the second a couple inches to the right, and the third a couple inches high. So my average groups are 7" or so, creeping high and to the right. Once I get the compression and hop-up dialled in Im hoping I can hold that 2 1/2" or better at 30 yards. My goal is to be able to make accurate lob shots at 200+ feet with heavy pellets, and have no MED to worry about closer in.

Edited by bark-eater

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One of my teammates bought this barrel and spent years talking about how great it was and how his gun was much better than my standard setup.

 

About 4 games without him getting any kills later he's given up and is getting a high fps build. This barrel is just some magical trickery that doesn't compare to a proper high fps heavy bb setup.

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One of my teammates bought this barrel and spent years talking about how great it was and how his gun was much better than my standard setup.

 

About 4 games without him getting any kills later he's given up and is getting a high fps build. This barrel is just some magical trickery that doesn't compare to a proper high fps heavy bb setup.

 

Oh my god, that's what all this TK Nonsense is then. Just trickery.

 

And for a second there I almost though it was just an impatient unskilled player making excuses on his equipment. Silly me. :a-laugh:

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I posted a topic about this a long time ago. No response or interest really. If I ever get around to it I'll personally fax TK. I have an interest in developing twist barrels for higher FPS ranges. I'll edit this later and add my topic. (not trying to threadjack, but to give some ideas to what the science is behind it)

EDIT: http://www.airsoftforum.com/board/Twist-Ba...amp;hl=Proposal

Edited by Frosty23

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Just use a bb that will bring the fps to around 330 fps. At 340 with a .2, use a .28 or a .3, and it should work great.

In earlier studies, it said an heavier bb to reduce fps will not make it work better. I just wanted to know if the slight fps increase will be too high that the barrel isn't effective any more.

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So how would you clean it? Do you just run water through the barrel or something? (and sorry about the necro post)

 

You know those plastic brush that you use to clean like bottles?

Use those, just make sure that that aren't too hard.....

 

Or get a real steel wool cleaning kit.

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You know those plastic brush that you use to clean like bottles?

Use those, just make sure that that aren't too hard.....

 

Or get a real steel wool cleaning kit.

 

 

Which brush should I get? There are different types of the brushes, and some look too stiff to use in the barrel without scratching it.

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Which brush should I get? There are different types of the brushes, and some look too stiff to use in the barrel without scratching it.

 

Go to a store that sells those and feel it with your hands.

I'd rather get a wool cleaning kit tho.

They aren't that expensive.

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If one was to reduce the rate of twist in the barrel, I bet it would perform at a higher velocity. It may be that the barrel spins the bb too fast at higher velocities, magnifying the effects of variations in the bbs

 

It makes sense then that you'll need a higher twist rate for a twist barrel to work on hotter guns, no?

 

It may be possible to make your your own twist barrel. You'll need to cut helical grooves on a mandrel with a minor diameter of say 6.02mm and the major diameter will depend how deep you want the groove to be. Insert the mandrel into your custom barrel which has an ID slightly larger than your mandrel major diamter/OD and "autofrettage" it by housing the custom barrel in a rigid hole. Proceed to compess both ends of your custom barrel by means of hydraulic assistance and voila, you have a twist barrel. Remove the mandrel by unscrewing it from the custom barrel.

 

Lol if anyone really tries this out let me know.

 

I also think you'll probably need some serious porting to increase accuracy since you're introducing excessive blow-by.

 

I'm not sure it it would work the same way in airsoft barrels, but this is how it works in firearms. Bullets of a given weight can be spun too fast. All bullets (and BBs) have imperfections. When overspun, the bullet will spin around the imperfection, instead of around it's center. You then have three choices, you can increase the weight of the projectile, which requires the higher twist rate to stabilize it, you can slow the bullet down so that it will spin at a slower rate, or you can get a barrel with less twist. I have a suspicion that the same may be the case in the twist barrel. That would explain this.

 

"There was another player in our local club ,who I got hooked on the TK, who put an M110 into his MP5, and it was shooting 365fps. His accuracy was total crap with .2 gram bbs (even worse than stock barrel), but when he put .28's into his gun it was phenomenal."

 

 

Edited by shadow man

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What do people think about the falcon straight rifled barrels? I know that they are only rifled the last couple of cm, but it may be like a few air rifle that are smooth bore except for the very end.

 

 

And yes I now that the bb in no way touches the lands and groves, but just the air around them...

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The hop up spins the bb, the twist barrel creates an air cushion so the bb doesnt hit the barrel walls as much. makes it float so it steadies the bb better thus better groupings and accuracy. this is not the same affect that rifled real steel barrels have with bullets.

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it still spins the bb. If it didn't, there wouldn't be an accuracy increase.

 

Sorry but which part of thread can you not read?

 

IF the BB is spinning because of the rifling, it'll :censored2: up the trajectory......

Did you not remember there's a thing called "hop up"?

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