hey sick video really informing about the roller guns I was wondering if you could only get on sized shaft for a roller which will be using 14mm and 16mm bands depending on the conditions which size would you prefer to pick for a 110cm roller
Hi Chris, what are you thoughts on converting a full pretension to a standard pretension set up and using just the single anchor point ? E.g. aimrite. Many thanks
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.
Brilliant. I am a new user of roller guns and to be honest my 90cm gun has been doing my head in. I reckon your videos are going to help me get it together and enjoy the technology. Cheers and keep up the awesome work.
Dose this apply to different guns say an Aimrite 120 roller where the bands still need the bridal to hook back to the lug? Would max pretension be a 60cm rubber or maybe Less because you need the bridal?
Legend! thank you for the video... I myself have been wondering the reason behind the full pretension vs normal and simply assumed they would perform almost the same with the exception the the travel force/distance to be more variable with the semi pretension version. SUPER VIDEO!! now we understand that loading is easier on the semi pretension but you will most likely feel more kick back leading to a slightly variable shot.
Really like the your content and article on rollers. I have just put together a 900 roller based on your article. Intend to use the 900 with a 6.5mm (for smaller reef fish) and 7mm shaft(as a backup shaft). Would it be possible for you to run through advantages of a lighter faster shaft to a heavier more penetrating shaft in your 900/1100 set up? Also would you go through the type of rubber you prefer, diameter, elasticity, micro bore and/pr standard bore, for each of your setups?
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.
Good Video, I have owned rollerguns but I gave them up as they had no power or range advantage over my riffe euro. I have seen a few videos where well setup conventional spearguns can equal or even outperform rollers, I think this is due to the fact that if setup properly a conventional speargun can achieve "maximum velocity" sooner than on the rollergun therefore done need the longer rubber drive. I am playing around with inverted roller superguns at the moment, the shot is really nice but when using 7mm spears, I am not convinced they are better than a normal roller or conventional speargun. Perhaps when going to a 8mm spear they have a advantage?
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.
Hey Chris great video once again ! I've done the calculations with my spearguns, I have a RA roller in 120cm with 14mm sigal sub rubbers (coeff 3,12) full pretension. Tension at the muzzle is 16,5kg and at the notch it is 38kg. The potential energy is 3270 kg/cm. Then I did the same with my blue water invert roller it is 125 speargun (with three pair of 16mm Primeline rubber coefficient 3,5, and one pair of 18mm rubber in "laser" coefficient 3,2) The tension at the muzzle is 37 kg, and at the notch it is 167kg, so the potential energy is 12750 kg/cm. But in my graph the line is pretty steep, parallel to the line of my double 16mm riffe euro 130. But the recoil is none, I guess it's because of the invert system. Are you going to do a video about th invert roller ? Cheers !
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 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.
I run the full pre tension on my rollers and love the rob allen roller bridle set you can buy, makes loading so easy and no longer need the load assist
Hello.. sorry i might have missed something.. standard pretension goes from 130% to 330% and the full pretension would be from 183% to 358% . If the full pretension is stretched more at the notch (358%), then i would think that the load at notch would be more than the std pretension (330%).. but the graph shows full pretension lower than std at notch? Im considering modifying a speargun from an inverted roller setup 😀
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.
Is the diagonal line on the diagram alwas straight or could it vary if u test diferent losing distances on the same setup? Would u alwas land on the line or could it have a sleight convex or concave shape in realive ?
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.
Really enjoy this series on roller guns and their setups. I currently have all my rollers set up as conventional. Will start by updating my Rob Allen 80cm gun to full pretension and compare it against my current setup. I do have one question. When talking "pretension" is there an ideal percentage of pretension that we should consider that can then be applied to all gun lengths (ie 10% pretension on a 70cm gun would be 7cm of preload, and thus 10% pretension on a 100cm gun would be 10cm)? Thanks again and look forward to your next episode!
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.
I plan on buying a 110 roller tomorrow...I was all set on the 7mm shaft with 14 mil bands, do you still recommend that setup over the 7.5 mm and 16mm setup?
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.
Even though accurate I think this is a bad comparison. If you are going to compare the 2 types of pretension at least go with the same rubber thickness
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.
Hey Chris from what I can see the muzzle slightly to bulky and it would be nice to have a flat clear view all the way down the spear! Would there be an issue if I had to grind it as flat as possible, maybe just flush with the spear? Another thing where the bands come to a stop, I believe at that point there is the most room for error as the beads bump into the rollers, lift and flip which could lift the tail of the spear as it exits and causes the spear to dive slightly...? With the bead band ends bumping into the rollers at that angle, it would deflect the muzzle possibly interfering with accuracy. Could you please explain this and let us know how much this effects the shot placement?
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.
Thanks for all this work and info. I am curious, I have a carbon fiber 120 cm standard gun with a cuttlefish barrel. I notice you all don't use cuttlefish barrels. Is there a reason why I wouldn't want to try this a a roller? Do they have more friction on the roller band because of it rubbing against the barrel? Or just never felt the need to try? I do like how this gun shoots as is but feel like it would be fun to try it as a roller, and could in the future quickly switch it back and forth with a change of the bands and muzzle and muzzle ballast.
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!
Excellent original article Chris and now the updates via awesome videos! Thank you. I've built a 900 and a 1100 RA aluminium barrel roller with 300mm 7mm spear overhang after reading your original article. Great guns but I find that the balance of both the guns in the water is noticeably front heavy compared to the RA double rubber guns - I suspect due to extra weight of roller muzzle. Barrels are well sealed. Once spear is discharged the gun sinks as well. Thinking of fitting a Pathos gun float or going Carbon barrel but I wondered if you found this as an issue and whether you solved it somehow? Thank you and I'm really looking forward to the rest of your series!
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.
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 and a simple question: full or standard pretensions must be related with rubbers dimension and diameter, what are the ratios? meaning, standard pretension make the rubbers length smaller, but should it be related with diameter? otherwise is only a question of larger or smaller length of rubbers, correct? thanks...
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)
I made up my own rubbers for the first time recently using 16mm manny sub progressive rubber. My gun is a 100 RA tuna roller and I made the rubbers to the same size as the rubbers that came on the gun (60cm) and set them at full pretension. I can’t load the gun even with a load assist, is this because they’re progressive rubber?
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
To measure all the loads did you do it with the full set ups on the guns or were you able to come up with the load that comes from a certain amount of band stretch?
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.
Idea, or theory, behind standard pretension had something to do with the gun shooting at a low trajectory, at least that's why I went back to standard pretension. You can load the Pathos Sniper-R without a loading assist in both full and standard pre-tension. The manufacturer still insists on only using standard, cause of the shaft getting overpowered. But this gun also has a kicker band. So dunno. Would be great to hear something about the low trajectory thing. Is this cause the wishbone is lifting the spear when it reaches the muzzle?
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??
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
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.
Brilliant and one of the most informative videos I’ve come across. Keep them coming. Helps when you can make an informed decision.
100% what set up did you end up going with?
hey sick video really informing about the roller guns I was wondering if you could only get on sized shaft for a roller which will be using 14mm and 16mm bands depending on the conditions which size would you prefer to pick for a 110cm roller
Keanu I would use a 7mm shaft for 14mm bands and 16mm bands.
With the 16mms you can also shoot a 7.5mm shaft.
my exact question.. thanks!
Hi Chris, what are you thoughts on converting a full pretension to a standard pretension set up and using just the single anchor point ? E.g. aimrite. Many thanks
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.
Great Video Chris, well done. Helps to get people involved these videos! Dive Safe!
Brilliant. I am a new user of roller guns and to be honest my 90cm gun has been doing my head in. I reckon your videos are going to help me get it together and enjoy the technology. Cheers and keep up the awesome work.
Dose this apply to different guns say an Aimrite 120 roller where the bands still need the bridal to hook back to the lug? Would max pretension be a 60cm rubber or maybe Less because you need the bridal?
Awesome work mate. Look forward to the rest of the series. Thankyou
Legend! thank you for the video... I myself have been wondering the reason behind the full pretension vs normal and simply assumed they would perform almost the same with the exception the the travel force/distance to be more variable with the semi pretension version. SUPER VIDEO!! now we understand that loading is easier on the semi pretension but you will most likely feel more kick back leading to a slightly variable shot.
Really like the your content and article on rollers. I have just put together a 900 roller based on your article. Intend to use the 900 with a 6.5mm (for smaller reef fish) and 7mm shaft(as a backup shaft).
Would it be possible for you to run through advantages of a lighter faster shaft to a heavier more penetrating shaft in your 900/1100 set up?
Also would you go through the type of rubber you prefer, diameter, elasticity, micro bore and/pr standard bore, for each of your setups?
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.
Very clear and informative videos! Have to admit the load assist thing is one of the things I'm not really keen on.
Good Video, I have owned rollerguns but I gave them up as they had no power or range advantage over my riffe euro. I have seen a few videos where well setup conventional spearguns can equal or even outperform rollers, I think this is due to the fact that if setup properly a conventional speargun can achieve "maximum velocity" sooner than on the rollergun therefore done need the longer rubber drive. I am playing around with inverted roller superguns at the moment, the shot is really nice but when using 7mm spears, I am not convinced they are better than a normal roller or conventional speargun. Perhaps when going to a 8mm spear they have a advantage?
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.
Very helpful video, Thanks from France
Hey Chris great video once again ! I've done the calculations with my spearguns, I have a RA roller in 120cm with 14mm sigal sub rubbers (coeff 3,12) full pretension. Tension at the muzzle is 16,5kg and at the notch it is 38kg. The potential energy is 3270 kg/cm.
Then I did the same with my blue water invert roller it is 125 speargun (with three pair of 16mm Primeline rubber coefficient 3,5, and one pair of 18mm rubber in "laser" coefficient 3,2) The tension at the muzzle is 37 kg, and at the notch it is 167kg, so the potential energy is 12750 kg/cm. But in my graph the line is pretty steep, parallel to the line of my double 16mm riffe euro 130. But the recoil is none, I guess it's because of the invert system.
Are you going to do a video about th invert roller ?
Cheers !
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 🤙🏼🔥
thanks so much for this series!!
I run the full pre tension on my rollers and love the rob allen roller bridle set you can buy, makes loading so easy and no longer need the load assist
Thanks for the info, brother.
Thanks bro!
Superb!!!!
Hello.. sorry i might have missed something.. standard pretension goes from 130% to 330% and the full pretension would be from 183% to 358% . If the full pretension is stretched more at the notch (358%), then i would think that the load at notch would be more than the std pretension (330%).. but the graph shows full pretension lower than std at notch? Im considering modifying a speargun from an inverted roller setup 😀
Hi Chris ! I don’t understand your job😅 you sell rob allen spearguns or you custom spearguns?
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!
Is the diagonal line on the diagram alwas straight or could it vary if u test diferent losing distances on the same setup? Would u alwas land on the line or could it have a sleight convex or concave shape in realive ?
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
Really enjoy this series on roller guns and their setups. I currently have all my rollers set up as conventional. Will start by updating my Rob Allen 80cm gun to full pretension and compare it against my current setup. I do have one question. When talking "pretension" is there an ideal percentage of pretension that we should consider that can then be applied to all gun lengths (ie 10% pretension on a 70cm gun would be 7cm of preload, and thus 10% pretension on a 100cm gun would be 10cm)? Thanks again and look forward to your next episode!
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.
how does the standard pretension end up having a higher output in kilograms when loaded than the full pretension?
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
I plan on buying a 110 roller tomorrow...I was all set on the 7mm shaft with 14 mil bands, do you still recommend that setup over the 7.5 mm and 16mm setup?
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.
Great video, congrats. What lenght do you cut the rubber bands for a 110/115 roller speargun!?
Best regards
Just go with the 'half barrel + 5cm' formula. 👌
Check out the video on 110 single rollers ua-cam.com/video/yVkuk0d3-ug/v-deo.html
Even though accurate I think this is a bad comparison. If you are going to compare the 2 types of pretension at least go with the same rubber thickness
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.
What is the difference in power an pretension between a regular roller gun an an inverted roller gun
There are many differences. Too many to cover here. Will have to do a couple videos on inverted rollers some time.
What is the length of each full pre-tension rubber before stretching them to the anchors.
with 14mm hand load its half the barrel length plus 5cm = 50cm 👍
should make the next video on band setup and the correct length for your gun and what mm is the best
Will cover band lengths and set ups for each gun size.
@@CoatesmansSpearfishing Can't wait for this one!
You rather standard 16mm bands for rollers or small id bands?
very little advantage of small ID bands. If anything I feel they make the rubbers feel stiffer. Just use good std ID
Hey Chris from what I can see the muzzle slightly to bulky and it would be nice to have a flat clear view all the way down the spear! Would there be an issue if I had to grind it as flat as possible, maybe just flush with the spear?
Another thing where the bands come to a stop, I believe at that point there is the most room for error as the beads bump into the rollers, lift and flip which could lift the tail of the spear as it exits and causes the spear to dive slightly...?
With the bead band ends bumping into the rollers at that angle, it would deflect the muzzle possibly interfering with accuracy.
Could you please explain this and let us know how much this effects the shot placement?
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.
Thanks for all this work and info. I am curious, I have a carbon fiber 120 cm standard gun with a cuttlefish barrel. I notice you all don't use cuttlefish barrels. Is there a reason why I wouldn't want to try this a a roller? Do they have more friction on the roller band because of it rubbing against the barrel? Or just never felt the need to try? I do like how this gun shoots as is but feel like it would be fun to try it as a roller, and could in the future quickly switch it back and forth with a change of the bands and muzzle and muzzle ballast.
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!
Excellent original article Chris and now the updates via awesome videos! Thank you.
I've built a 900 and a 1100 RA aluminium barrel roller with 300mm 7mm spear overhang after reading your original article. Great guns but I find that the balance of both the guns in the water is noticeably front heavy compared to the RA double rubber guns - I suspect due to extra weight of roller muzzle. Barrels are well sealed. Once spear is discharged the gun sinks as well. Thinking of fitting a Pathos gun float or going Carbon barrel but I wondered if you found this as an issue and whether you solved it somehow?
Thank you and I'm really looking forward to the rest of your series!
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 and a simple question: full or standard pretensions must be related with rubbers dimension and diameter, what are the ratios? meaning, standard pretension make the rubbers length smaller, but should it be related with diameter? otherwise is only a question of larger or smaller length of rubbers, correct? thanks...
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
I made up my own rubbers for the first time recently using 16mm manny sub progressive rubber. My gun is a 100 RA tuna roller and I made the rubbers to the same size as the rubbers that came on the gun (60cm) and set them at full pretension. I can’t load the gun even with a load assist, is this because they’re progressive rubber?
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
To measure all the loads did you do it with the full set ups on the guns or were you able to come up with the load that comes from a certain amount of band stretch?
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.
Idea, or theory, behind standard pretension had something to do with the gun shooting at a low trajectory, at least that's why I went back to standard pretension.
You can load the Pathos Sniper-R without a loading assist in both full and standard pre-tension. The manufacturer still insists on only using standard, cause of the shaft getting overpowered. But this gun also has a kicker band. So dunno.
Would be great to hear something about the low trajectory thing. Is this cause the wishbone is lifting the spear when it reaches the muzzle?
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.