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Old 05-31-2017, 03:23 PM   #1
vstante
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Roisub 115 Demo3

Hi guys, anybody else shoots that gun? Just bought the gun recently and took it to the pool with me twice. The gun shoots dead center 2cm high on 4.5 and 5.5m, but on longer distances, the shooting line got tangled with the rubbers. I think it happened because I was using a 1,2mm climax. I should go back to 1,2mm mono nylon probably.
I dont know whats the band stretch. The gun is 140cm long but it feels very light underwater. I have a constant feeling I am operating with a much smaller/shorter gun. Equiped with a 8mm 155cm shaft. The bands are 2x21mm and 4x 16mm.
The gun has also a special dyneema loader. (http://www.roisub.net/ogiva-demo.html) It works well, but I dont like that, I am going to change it with a pair of 16mm bands with internal dyneema.

Anybody have any experiences with that gun?
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Old 06-10-2017, 04:36 AM   #2
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Re: Roisub 115 Demo3

So, just installed the fusion kit on the gun. The DEMO3 is the top line of the Roisub System and the most powerfull. However, You can choose between different gun lenght and systems. Demo3, Fusiondemo3 (with 2 kicker bands) and Fusiondemo3 Big Shaft (with 8,5mm shaft).




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Old 06-10-2017, 08:07 AM   #3
lagfish
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Re: Roisub 115 Demo3

Nice. How does it shoot? Does the top band have dyneema through the middle to prevent overstretching? I think a rail gun is a good platform for an inverse roller because one of the main benefits is the reduced recoil so you don't necessarily need the mass of a wood gun to absorb the smaller recoil. Why is there a loop of dyneema between the pulley block and bands? Seems like you could get more energy into the system by removing the loops and attaching the bands directly.
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Old 06-10-2017, 01:59 PM   #4
seal77
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Re: Roisub 115 Demo3

Have any one tried penetration test with that gun?I was always wondering why is that long band up,wich is reducing the real roller loading lenght and eventualy reducing the polispast effect.
This type of guns are usually shooting accurately but I wonder if it can pass a heavy penetration test at 5-6 meters
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Old 06-12-2017, 03:11 PM   #5
vstante
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Re: Roisub 115 Demo3

Quote:
Originally Posted by lagfish View Post
Nice. How does it shoot? Does the top band have dyneema through the middle to prevent overstretching? I think a rail gun is a good platform for an inverse roller because one of the main benefits is the reduced recoil so you don't necessarily need the mass of a wood gun to absorb the smaller recoil. Why is there a loop of dyneema between the pulley block and bands? Seems like you could get more energy into the system by removing the loops and attaching the bands directly.
Hi Lagfish, the dyneema loop there is to reduce/popweup the gun. At the beginning, when the bands are not strerchet out yet, you can use that loop no not the overpower the gun and than, with the time remove it. Thats what the roisub staff is saying. When I was shooting the demo3 system in the pool, I removed the dyneema loops, since there is no need for it. The fusion system is more powerful, I will test it in two days and write more about it. The gun was shooting accurate on 4 and 5m, a bit high but center.
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Old 06-12-2017, 03:16 PM   #6
vstante
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Re: Roisub 115 Demo3

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Originally Posted by seal77 View Post
Have any one tried penetration test with that gun?I was always wondering why is that long band up,wich is reducing the real roller loading lenght and eventualy reducing the polispast effect.
This type of guns are usually shooting accurately but I wonder if it can pass a heavy penetration test at 5-6 meters


Hi there, I am using styrosomething for a target, 5cm thick. It equals a medium sized dentex. The gun penetrates the target at 5 and 5.5m fully.

About the kicker-bands. I was wondering the same. Well, the upper bands have dyneema inside, so they can not overstretch. I think its the same idea, as having another 16mm band on the gun, to give some more speed to the shaft??

What is a heavy penetration test? Is that the fat penetration thing Majd8 is using in his tests?
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Old 06-16-2017, 04:03 PM   #7
vstante
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Re: Roisub 115 Demo3

what a disappointment today after shooting on the target. Distance from shaft to target 5 and 6m. The shaft is very unstable and impacting high left. I missed the whole target
a few times. I am still not shure, if the bands are hitting the shooting line. One shot felt very different and it was center perfect hight. The shaft is 8mm 150cm 1 flopper down.
Any suggestions what to do for better accuracy?


Last edited by vstante; 06-18-2017 at 04:36 AM.
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Old 06-17-2017, 05:22 AM   #8
Azure Recluse
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Re: Roisub 115 Demo3

I was interested to see how the roisub would shoot for you, thanks for sharing your results. I am yet to find a pipe gun style roller or invert roller that performs well and matches the price point. My mate bought a mannysub invert roller here in australia and it was very disappointing, especially because it was over a grand to buy. We both tried it over multiple dives but it ended up in the boat most of the time.... even with different configurations. He also has a few rob allens converted to roller guns and a regular mannysub roller gun... has been tuning them for the past 2 years and spent a crap ton of money on all the gear. He said to me the other day.... "maybe i should go back to regular band guns."

Perhaps custom wooden/ carbon roller and invert rollers are the way to go... I just have not been impressed with the performance benefits of buying a roller muzzle and putting it onto a pipe gun. The MVD muzzles were even worse. Hopefully you can tune the roisub to shoot a little better.

I have to say though, I experimented with a Rob Allen 90cm carbon roller for my last few dives and in my opinion, it is the best roller pipe gun I have used. Simple and rugged... probably not a gun I would hunt with on a regular basis but something I would add to the arsenal
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Old 06-17-2017, 01:07 PM   #9
lagfish
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Re: Roisub 115 Demo3

Quote:
Originally Posted by vstante View Post
what a disappointment today after shooting on the target. Distance from shaft to target 5 and 6m. The shaft is very unstable and impacting high left. I missed the whole target
a few times. I am still not shure, if the bands are hitting the shooting line. One shot felt very different and it was center perfect hight. The shaft is 8mm 150cm 1 flopper down.
Any suggestions what to do for better accuracy?

You can try shooting without the line and just the shaft to see how much accuracy improves.
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Old 06-17-2017, 01:36 PM   #10
vstante
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Re: Roisub 115 Demo3

Hi there!

@Azure Recluse
Well, I also hunt with a wooden high-end monoroller. Its a great gun, but also not perfect.
I have to say, I like Roisub. I changed the setup, so I think I will have to tune it a bit. I like the gun, because its very slim and maneuverable under water, I have a feeling I am using a much shorter gun.

@lagfish

I also removed the line, but it was hard to see it, because of the shaft speed. (I will try next time with a camera) As I could see, the shaft was flying tip high and two times even penetraiting the surface of the pool. I think, I might have overpowered the gun...
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Old 06-17-2017, 01:50 PM   #11
Josec84
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Re: Roisub 115 Demo3

Quote:
Originally Posted by Azure Recluse View Post
I was interested to see how the roisub would shoot for you, thanks for sharing your results. I am yet to find a pipe gun style roller or invert roller that performs well and matches the price point. My mate bought a mannysub invert roller here in australia and it was very disappointing, especially because it was over a grand to buy. We both tried it over multiple dives but it ended up in the boat most of the time.... even with different configurations. He also has a few rob allens converted to roller guns and a regular mannysub roller gun... has been tuning them for the past 2 years and spent a crap ton of money on all the gear. He said to me the other day.... "maybe i should go back to regular band guns."

Perhaps custom wooden/ carbon roller and invert rollers are the way to go... I just have not been impressed with the performance benefits of buying a roller muzzle and putting it onto a pipe gun. The MVD muzzles were even worse. Hopefully you can tune the roisub to shoot a little better.

I have to say though, I experimented with a Rob Allen 90cm carbon roller for my last few dives and in my opinion, it is the best roller pipe gun I have used. Simple and rugged... probably not a gun I would hunt with on a regular basis but something I would add to the arsenal
I have a cressi Geronimo 100 with a mantis roller head that the guys at neptonics set up for me and it shoots fantastically. I think it comes down to dialing your setup. Not sure if I got lucky or if Neptonics accounted for the shaft and green bands, but my gun is very accurate and precise. Don't give up on rollers.
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Old 06-17-2017, 02:07 PM   #12
lagfish
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Re: Roisub 115 Demo3

Quote:
Originally Posted by vstante View Post
Hi there!

@Azure Recluse
Well, I also hunt with a wooden high-end monoroller. Its a great gun, but also not perfect.
I have to say, I like Roisub. I changed the setup, so I think I will have to tune it a bit. I like the gun, because its very slim and maneuverable under water, I have a feeling I am using a much shorter gun.

@lagfish

I also removed the line, but it was hard to see it, because of the shaft speed. (I will try next time with a camera) As I could see, the shaft was flying tip high and two times even penetraiting the surface of the pool. I think, I might have overpowered the gun...
I think so too. Try using a 8.5mm shaft?
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Old 06-17-2017, 03:22 PM   #13
vstante
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Re: Roisub 115 Demo3

Well, I am afraid to loose some shaft speed with the thicker shaft. But I was thinking to try another stiffer 8mm shaft, maybe Pathos? Not shure, what shaft is orig. ROISub, (looks like Devotosub), but I have a feeling the shaft is very soft.
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Old 06-17-2017, 03:28 PM   #14
lagfish
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Re: Roisub 115 Demo3

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Originally Posted by vstante View Post
Well, I am afraid to loose some shaft speed with the thicker shaft. But I was thinking to try another stiffer 8mm shaft, maybe Pathos? Not shure, what shaft is orig. ROISub, (looks like Devotosub), but I have a feeling the shaft is very soft.
Unless you're actually permanently bending the shaft, the difference in flexibility of different types of steel is the same. The modulus of elasticity is about the same +/-10% for a hardened stainless steel, hardened tool steel, or regular carbon steel. So I don't think switching to a different shaft of the same diameter will make a big difference.

You will actually lose shaft speed if you overpower a thinner shaft that is whipping and doesn't have a straight trajectory than if you went with a bigger shaft
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Old 06-17-2017, 03:39 PM   #15
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Re: Roisub 115 Demo3

Dial back on power until it's right and then slowly increase? The thinner shaft may be getting overpowered? Video is the solution. There's many different things that can throw off a shaft trajectory with a 'spray pattern'. Dialing in guns is not easy. Video and process of elimination help.
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