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

Johnny Raro said:

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?

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Sorry mate vis has been crap 4 mtrs at best need a little more for testing? Next month should bring the blue in!

Ok so I finally got to test my RA 110 Double Roller. First impressions was that it appears to be dead accurate at approx 5m. Very little recoil, easy to shoot. So far so good! Will keep you posted when I've had more of a chance to test it out.!

I have a 115 salvimar roller metal with a double roller set up now. It has 14mm salvimar acid rubber which I think delivers the perfect blend of progressive energy with out throwing my shot off. 16m would be over kill and wouldn’t be much of an advantage over the 14mm. In pool test I was able to hit a target a 20+ feet no problem with very little shot drop.

la_mine97139 said:

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!

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Also Gianni, if you keep the shaft short off the muzzle with little over hang and go stainless, you can still maintain fast shaft speeds without jodiendo your shot. More than enough for big snappers and BIG cuda’s, my shots with This set up typically goes right through and keeps going

I built a RA 120 carbon with an MVD double roller and reverse mech in 2017. Initially tried 16mm bands, but they overpowered the gun when loaded to proper prestretch. I switched to 14mm low id rubber at 350% and 150% prestretch with a medium length pull and 7.5mm double flopper shaft, that’s the best setup. I suggest reading Chris Coates article on roller guns for band setup, it’s very thorough and goes through 3 different style setups for roller bands and explains results.

I used the gun in Baja for Wahoo, YT and AJ, and in CA for WSB/YT. It is super accurate to the end of double wrap. The 14mm low id setup is definitely the way to go. I’ve taken down 50 plus fish with this gun and I know if I miss, it’s because of my aim, not the gun.

Okay sorry guys in answer double roller double 16s snapped my gun twice old carbon one which could have been dropped?.. Super overpowered with an 16mm and 8mm shaft.

Have played around now with double and single rollers and found the sweet size is 110. I used a rob Allen Carenax Cut down to 110. Very happy with results basically the formula I used is 14mm rubbers for both single and double roller stretched 350-400%. Ie 100% preload. The double I find a little heavy on the nose with an 8mm shaft it shoots very hard and straight with great power possibly a bit of an overkill unless Blue Water hunting for fish 30kilo plus. I’m picking maybe up to a metre more range than a single.

The RA single is ample power for me for big King Fish The 14mm delivered unbelievable power and love the Single it’s like a laser with a 7.5 mm shaft 110 I find way better lateral movement when tracking fish 120 was a little long and too hard to load and I refuse to carry or use a load assist. (I would just lose it anyway) Range I’m guessing a pretty confident kill on a bigger fish in 5-6 meters they drop like a stone with the bigger shafts. Well worth the time playing good fun.