Little speargun project: Rob Allen carbon 120cm+ MVD Double Roller Head

[la_mine97139]

Hello,

I am Gianni From Guadeloupe, living in FL!

I own a RA Alu 100cm, Mantis Roller Head with 14mm single band and 7mm shaft.

As my dive time and dephs improved a lot, I need a new gun for deep deph 80ft-115ft spearfishing big cubera, mutton and dog snapper and maybe blue water on wahoo and mahi-mahi . I am looking for 16feet-23feet range for cautious fish(I don't know which word to use to describe it) fish, I mean fish over 13lbs that doesn't approach close and keep a good distance.


I would like to couple a RA 120cm with the new MVD Double Roller Head and 16mm bands.

As I didn't find any review about it, I have a few questions:

What do you think about the idea?

I didn't do any calcul but I is the double roller muzzle head will unbalance the gun? Because it must be a little heavier than the stock closed muzzle;

Should I use a 7mm, 7.5mm or 8mm shaft?


Sorry for my non-academic english!

And thanks for your time to help me!

 

[Nicko]

Would anything less than an 8mm shaft on a 120 16mm double roller be overkill?
I hope you try it and post it up...sounds good. Would definitely require some flotation and I'm pretty sure MVD supply stick on floats for that very reason.

 

[thehok]

Hello,

I am Gianni From Guadeloupe, living in FL!

I own a RA Alu 100cm, Mantis Roller Head with 14mm single band and 7mm shaft.

As my dive time and dephs improved a lot, I need a new gun for deep deph 80ft-115ft spearfishing big cubera, mutton and dog snapper and maybe blue water on wahoo and mahi-mahi . I am looking for 16feet-23feet range for cautious fish(I don't know which word to use to describe it) fish, I mean fish over 13lbs that doesn't approach close and keep a good distance.


I would like to couple a RA 120cm with the new MVD Double Roller Head and 16mm bands.

As I didn't find any review about it, I have a few questions:

What do you think about the idea?

I didn't do any calcul but I is the double roller muzzle head will unbalance the gun? Because it must be a little heavier than the stock closed muzzle;

Should I use a 7mm, 7.5mm or 8mm shaft?


Sorry for my non-academic english!

And thanks for your time to help me!

Hey Brother,

Any update on the double roller gun as I was looking for a review too but couldn't find any.

I have a rail gun "SEAC OCEAN FIRE 105cm" removed the old head and installed a single band roller. I was really shocked on how much distance a roller gun can shoot the shaft. but I wanted more power so I was thinking to upgrade it again to a double roller MVD head.

if you got any review please shear it on brother. ^_^

All the best.
Thehok

 

[MattG]

Hello,

I am Gianni From Guadeloupe, living in FL!

I own a RA Alu 100cm, Mantis Roller Head with 14mm single band and 7mm shaft.

As my dive time and dephs improved a lot, I need a new gun for deep deph 80ft-115ft spearfishing big cubera, mutton and dog snapper and maybe blue water on wahoo and mahi-mahi . I am looking for 16feet-23feet range for cautious fish(I don't know which word to use to describe it) fish, I mean fish over 13lbs that doesn't approach close and keep a good distance.


I would like to couple a RA 120cm with the new MVD Double Roller Head and 16mm bands.

As I didn't find any review about it, I have a few questions:

What do you think about the idea?

I didn't do any calcul but I is the double roller muzzle head will unbalance the gun? Because it must be a little heavier than the stock closed muzzle;

Should I use a 7mm, 7.5mm or 8mm shaft?


Sorry for my non-academic english!

And thanks for your time to help me!

I just finished building an RA Tuna 110cm with a MVD double roller and 16mm bands, MVD sell a "complete" kit that includes stick on barrel floats made of wood to better balance for the additional weight.
I'm using an 8mm shaft to hopefully reduce whip and increase momentum through the water.
Haven't tried it yet as I'm waiting for the sealant to dry (used sealant to add additional protection to the wood and seal it against the barrel). Also it's winter here so water is down to 11 degrees Celsius and the visibility has been crap!
Will post results when I test it out!

 

[la_mine97139]

I just finished building an RA Tuna 110cm with a MVD double roller and 16mm bands, MVD sell a "complete" kit that includes stick on barrel floats made of wood to better balance for the additional weight.
I'm using an 8mm shaft to hopefully reduce whip and increase momentum through the water.
Haven't tried it yet as I'm waiting for the sealant to dry (used sealant to add additional protection to the wood and seal it against the barrel). Also it's winter here so water is down to 11 degrees Celsius and the visibility has been crap!
Will post results when I test it out!

Cool! Let me know when you get a chance to test it!

By the way I didnt start my project as I bought an impaler hybrid speargun 120cm. I still will have the chance to change the muzzle to a MVP double roller .

 

[Spareit]

Be interested also tested the gun yet? What length rubbers did you use.

Building a RA120 Carbon Double Mvd roller aswell so keen on any advice on pitfalls.

 

[MattG]

Be interested also tested the gun yet? What length rubbers did you use.

Building a RA120 Carbon Double Mvd roller aswell so keen on any advice on pitfalls.

Winter just ended here in Aust. Heavy rain and flooding causing zero visibility, and generally not good conditions. Hoping to get out next few weeks and test it out.

 

[Spareit]

Winter just ended here in Aust. Heavy rain and flooding causing zero visibility, and generally not good conditions. Hoping to get out next few weeks and test it out.

Cheers yup same Here in Hawkes Bay NZ mud town this time of year. What length rubbers did you use? And 16's? I guess. Rigged mine at 650 16's small dia hold man they are dam hard to load. Might need a rethink. I can use them on my smaller roller anyway. Need to find a speargun friendly pool owner! I am thinking there will be quite a few tweaks until it is bang on.

 

[Spareit]

Hello,

I am Gianni From Guadeloupe, living in FL!

I own a RA Alu 100cm, Mantis Roller Head with 14mm single band and 7mm shaft.

As my dive time and dephs improved a lot, I need a new gun for deep deph 80ft-115ft spearfishing big cubera, mutton and dog snapper and maybe blue water on wahoo and mahi-mahi . I am looking for 16feet-23feet range for cautious fish(I don't know which word to use to describe it) fish, I mean fish over 13lbs that doesn't approach close and keep a good distance.


I would like to couple a RA 120cm with the new MVD Double Roller Head and 16mm bands.

As I didn't find any review about it, I have a few questions:

What do you think about the idea?

I didn't do any calcul but I is the double roller muzzle head will unbalance the gun? Because it must be a little heavier than the stock closed muzzle;

Should I use a 7mm, 7.5mm or 8mm shaft?


Sorry for my non-academic english!

And thanks for your time to help me!

Hi there did you have any progress on this one? That gun is exactly what I am build ATM with a RA carbon 1200. 8mm shaft. I have been told if using a. Vectra 1 handle upgrade mech to be to a Vec 2 as they are built for the extra loading of a roller.

Now just figuring what length to cut the rubbers for optimism power v being able to load by hand.

 

[MattG]

I used 16mm rubbers cut at 55cm lengths, pretension is an additional 20cm. I added some clear plastic tubing to the loading loops to make loading more comfortable.

Also using a manny sub 8mm 150cm shaft with 5 shark fins (they have stopped making these so in the future will use the 3 fin version). I used this because it has a fin half way along the shaft which can be used to power down the gun for use in reef locations and to use as a mid load point to make it easier to load. I think the extra diameter of the shaft will also help reduce potential shaft whip caused by the additional power of the roller heads while adding to momentum of the shaft over distance.

Only thing is the mannysub shaft has 3 attachment points for the shooting line, I found the rear point interfered with loading the shaft into the Vecta2 Mech as I am using Dyneema instead of mono. The forward attachment for the shooting line is a loop welded to the top of the shaft and had to be removed using my Dremel as it sits quite high and will potentially interfere with the lines as it passes through the roller head.
I got the full conversion kit from MVD which included wood floats that attach to the sides of the RA.
I found the following YouTube Video very helpful:

 

[Spareit]

Sweet looks good, waiting for clean water and let the testing begin.

 

[Spareit]

Sweet looks good, waiting for clean water and let the testing begin.

 

[Spareit]

Here's my gun build, now a little shorter took another 50mm off muzzle end. Have left rubbers adjustable for tweaking 630 rubbers. Now the wait for clear water! 120ish RA Double MVD 16mm small ID rubbers 8mm shaft.

 

[kwtony]

If you could add a way to add a second stage for both bands and were able to make the bottom hook for the roller closest to the flopper a bit wider so the bands don't rub against themselves upon contraction and lay flat instead of on top of each other, you'd have one hell of a gun. Its pretty slick now and would probably shoot okay, but with some tweaking and some tuning I bet this could be accurate beyond 6-7 meters.

Is that a new carbon gun or is that one of the older style carbon tubes?

 

[Spareit]

If you could add a way to add a second stage for both bands and were able to make the bottom hook for the roller closest to the flopper a bit wider so the bands don't rub against themselves upon contraction and lay flat instead of on top of each other, you'd have one hell of a gun. Its pretty slick now and would probably shoot okay, but with some tweaking and some tuning I bet this could be accurate beyond 6-7 meters.

Is that a new carbon gun or is that one of the older style carbon tubes?

Yeah good points older gun Zulu I think? Was thinking attaching at hook for the bottom rubber to a hook on the base also. I will test it as is and refine from there unfortunately not likely in next month due to water clarity around here but will keep tweaking. Cheers for the feedback and good ideas.

 

[la_mine97139]

I used 16mm rubbers cut at 55cm lengths, pretension is an additional 20cm. I added some clear plastic tubing to the loading loops to make loading more comfortable.

View attachment 42654
View attachment 42655
Also using a manny sub 8mm 150cm shaft with 5 shark fins (they have stopped making these so in the future will use the 3 fin version). I used this because it has a fin half way along the shaft which can be used to power down the gun for use in reef locations and to use as a mid load point to make it easier to load. I think the extra diameter of the shaft will also help reduce potential shaft whip caused by the additional power of the roller heads while adding to momentum of the shaft over distance.
View attachment 42656
Only thing is the mannysub shaft has 3 attachment points for the shooting line, I found the rear point interfered with loading the shaft into the Vecta2 Mech as I am using Dyneema instead of mono. The forward attachment for the shooting line is a loop welded to the top of the shaft and had to be removed using my Dremel as it sits quite high and will potentially interfere with the lines as it passes through the roller head.
I got the full conversion kit from MVD which included wood floats that attach to the sides of the RA.
I found the following YouTube Video very helpful:

This looks insane!! great job man! Can't wait for you to test it. Should be accurate at a 5m-6m ranger without any problems!

Just hope the carbon barrel will handle the power of this double roller muzzle!

 

[Johnny Raro]

any more updates on the testing guys? i have a 110RA single roller I am thinking of converting to a double roller.

It's got a 7mm riffe shaft with a slip tip currently, do you think i can get away with that or have to go to an 8mm?

 

[Manuel Guerrero]

I purchased the MVD Double Roller months ago. Put it on a 120cm Hammerhead Karbon and a 100cm Hammerhead Karbon... it might be my setup BUT, I could not hit a thing with it. Not sure if it's the barrel bending, or shaft whip. Some who have seen my videos said I was to far away... I dunno. But the first impression it left with me was not good. I love rollers and love the product however. Sturdy and awesome.

 

[Spareit]

View attachment 42752 View attachment 42751 I purchased the MVD Double Roller months ago. Put it on a 120cm Hammerhead Karbon and a 100cm Hammerhead Karbon... it might be my setup BUT, I could not hit a thing with it. Not sure if it's the barrel bending, or shaft whip. Some who have seen my videos said I was to far away... I dunno. But the first impression it left with me was not good. I love rollers and love the product however. Sturdy and awesome.

Is that how you thread your shooting long, if so I would imagine that could be your issue? We haven't been able to test mine yet vis has been crap and want some nice water to test run. What stretch did you get out of your rubbers?

 

[Spareit]

Is that how you thread your shooting long, if so I would imagine that could be your issue? We haven't been able to test mine yet vis has been crap and want some nice water to test run. What stretch did you get out of your rubbers?

Also what size shaft 7.5 or 8ml?