Hey Mathew There is a fine balance when going thinner on the shafts. Too thin and the shaft whips. The up side is that the drop in profile and drag make the shaft fast and accurate. Will be sure to bring this and rubbers up in coming videos.

Keanu I would use a 7mm shaft for 14mm bands and 16mm bands. With the 16mms you can also shoot a 7.5mm shaft.

Hey Kevin, Barrel buoyancy is a big issue with all spearguns. Rollers have additional weight at the muzzle with bearings and metal axles etc. I will be covering this with each size gun.

@@CoatesmansSpearfishing Thanks for taking the time Chris and also for sharing your knowledge with your articles!!!

i just cut my 120 carbon barrel shorter to a 110 barrel, sealed it back up and attatched the roller muzzle with the ballast, havent tried it yet but i figure if i have a shorter barrel and a shorter shaft the ballast shouldnt be the same weight as before... rob allen only sells one size and weight of muzzle ballast... how could i balance my carbon roller gun perfecty? cut chunks or trim off the ballast and fit until the gun feels right?

Hi Roland, Should be trying to ensure that your final tension is at 300 to 350%. On a 800 your will be looking at having rubbers that are at 360mm, but saying that I usually try to make it so I am comfortably loading, not usually an issue with a 800.

Just go with the 'half barrel + 5cm' formula. 👌 Check out the video on 110 single rollers kzfaq.info/get/bejne/r7ybqM5hyZmRpZs.html

DiverGazz conventional guns are 100% obsolete, there is no way a conventional gun competes with a properly setup rollergun. Inverted guns are amazing but even more difficult to get right than a std roller.

@@CoatesmansSpearfishing Hey Chris, would you be able to explain this to us more. Really keen to understand why you have landed at this point re conventional vs roller? I'm all about shooting fish, so really interested how you have moved from the 1300 with 20mm, to a 1100 with twin/single? 14mm bands.

I like my bands to drive the shaft right to the muzzle of the gun. When you reduce the pretension point, you lower the load on the muzzle, and the ability to drive the shaft at the muzzle. So no I would still go full pretension.

Hey Andrew, I have spent the last 4 or 5 years developing a 'cuttlefish' barrel as I could not find one that was designed for rollerguns. Most of them the rubbers bow around the belly of the barrel. Hope to have product out there soon. So for now just sticking to the std carbon barrels.

@@CoatesmansSpearfishing Thanks! If I used that barrel they would definitely bow around it so maybe its not the best candidate to try a roller with. We appreciate you sharing all this great information!

Will cover band lengths and set ups for each gun size.

@@CoatesmansSpearfishing Can't wait for this one!

On a single roller you can go as low as shaft thickness, as long as there is enough clearance on the shaft to pass. Theoretically at least. Production muzzles have to accommodate the fact that someone might use shark fins or pinned shafts. Primarily for easy of loading so the fins clear under the bridle when loading. You are right that the rubber & bridle should not interfere with the shaft at the muzzle. Some muzzle unfortunately don't take all of these issues into account. I am going to have to do a whole video on bridle lift and how to overcome it.

@@CoatesmansSpearfishing Thanks alot Chris you are a brilliant help. I know this emerging sport is still relatively new compared to others, there is still alot to improve on, which is awesome for us. I have come up with two simple solutions, 1- eliminating the muzzle "flip" which makes it more accurate. 2- Loading of the roller gun without an external load assist which is a pleasure to fullyload. I will try put together for viewing in the near future. Cheers mate.

The 7mm / 14mm setup is better balanced buoyancy wise on a std RA carbon roller. The 7.5mm / 16mm combo has lethal power but is heavy in the water. If you have specific large fish in the 20+kg range that you are hunting then the 7.5m/16mm setup is the way forward.

Hey Raphael inverted guns are not multipliers but dividers. The pulleys divide the power. And like rollers there is an amount of energy loss around each of the pulleys. Did you measure the loads with a scale on the gun?

@@CoatesmansSpearfishing yes i did, I’ve add each tension of each rubber when loaded.

@@CoatesmansSpearfishing the pulley devide the power by 2 ? So when I’ve calculed the pretension it is divided by two so to have the real pretension I have to multiply by 2 ?

@@RaphaelSerrecombe The energy calc is right around 12750 kg/cm. The graph is steep not unlike a conventional gun. But the energy transfer around rollers be it a single or multiple pullies is slower and not as direct as a conventional gun. This is why you need a 14mm kicker on an inverted gun to get the shaft moving. But this energy lag is what I believe reduces the recoil. The energy is still transferred into the shaft, just not as explosively as a std conventional rubber.

@@CoatesmansSpearfishing okay really nice ! Thanks chris ! A pleasure to talk about that with you 🤙🏼🔥

with 14mm hand load its half the barrel length plus 5cm = 50cm 👍

It is a short 55cm 18mm band that at load is 330% which is almost 60kg. 16mm would have to be at 400% to load 60kg

Jarrad, I landed up doing both. For the band stretch model I build I used data from band stretch tests, to get the loads on ea diameter at specific percentages. I also rigged up a gun with scale to validate that study. And to see if there were any differences.

@@CoatesmansSpearfishing did you find it to be a pretty good representation of the actual band load?

in practice the values were slight higher than the model. Especially like on the muzzle where any friction or drag increased the load.

@@CoatesmansSpearfishing thanks.

Hey Patrick, You right the line will not be exactly straight as the load will vary as you take the shot. But more importantly which is not shown here is the snap back velocity of the rubber. This is something I will have to explain in another video.

thanks great teck video

There are many differences. Too many to cover here. Will have to do a couple videos on inverted rollers some time.

The question are obviously considering the same guns dimension...

Pedro, when is comes to std setups it is difficult to give an exact answer. Because how long is a piece of string. On a full pretension no matter what the gun or muzzle is all you do is measure the distance from the notch around the roller to the loading luggs and divide by 3.6 (can go shorter ... 360% is comfortable)

@@CoatesmansSpearfishing Noted and thanks, believe it's kind of try & error for the best settings.

So when I did this calculation and I came up with rubbers that measure around 13 inches on a 120 cm gun. This seems like I did something wrong haha

Std pretension & full pretension, if both are setup well, there should be no issues with shooting in a low trajectory. If you are using 16mm bands it will be almost impossible to load by hand as the muzzle load is over 25kg. " The manufacturer still insists on only using standard, cause of the shaft getting overpowered." This is crap. They add a kicker... what is that all about if they are worried about overpowering. Kickers are only functional / needed on inverted rollers. You should be able to get more than enough power out of basic roller setups with out needing to go add a kicker. Kicker = Recoil If the bridle is riding up the rail, it will lift the back of the shaft or make the shaft wobble. The bridle will only lift on a badly designed muzzle. Pathos have a stopper on their rail, but it is very low/short. Possibly needs to have 6.6mm shaft??

@@CoatesmansSpearfishing WoW! Thank you so much, Chris. This helps A LOT!

Dunno about the 6.6mm shaft. But the Pathos shoots a little bit low if fully powered. Maybe I will give everything a try without the kicker-band. As you said, I also think it is not as good as it sounds

What length gun?

It's a Sniper-R 85. Sorry, should have mentioned. The wishbone stopping unit, wish should stop the wishbone from pulling up the rear end of the spear, seems not to be designed 100% perfect. Lot of people take away some material of this "muzzle bridge", so the wishbone rises faster at the end, and say that the low trajectory problem got a little better, but still present.

My go to 16mm set up on a 100 is 55cm (natural dipped latex rubber) This is easy to load with a 14mm load assist. What load assist are you using?

Coatesman's Spearfishing just the RA load assist that came with the gun. I will add that I couldn’t load the gun whilst I was setting it up (out of water) so I set it up as standard pretension so I could load it. Should I try load it in water at full pre tension?

@@MrMarcustree I would try in the water for sure. Also, full pretension when you aren’t used to it is a bitch the first few times to get started. Do your rubbers come up around the pulleys at all before loading?

Thanks Tom, that’s the thing though, I am used to it because the factory rubbers were full pretension which is why I thought it’s maybe to do with the change in rubbers? The rubbers were under the pulleys at full pretension

@@MrMarcustree rig up your wishbone a bit shorter so rubbers are sitting on the roller a little. Makes it sooo much easier to get started

very little advantage of small ID bands. If anything I feel they make the rubbers feel stiffer. Just use good std ID

Hey Arthur, I build guns using some RA components. Those primarily being the handle and shafts. Being here in SA and close to the Dive Factory it just makes sense for me. Well that and the fact that I have not found anything that's better to replace them with. I am not exclusive to RA and build with various other brands. But its generally a compromise and my barrels and muzzles are designed to work with the RA spec. Always on the lookout tho and if you have any good ideas I am all ears.

@@CoatesmansSpearfishing everything is clear now! 😉 thanks a lot!

Hey Aldo if you go with the same rubber thickness there is no comparison at all. I chose the two examples as they have the same energy / power output and similar performance in practice.