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Old 03-04-2019, 11:29 PM   #1
BenGreen
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Band width for carbon gun

So I have a Bleutec Blackeyes carbon gun that I love. Question is I currently have 3 14mm small Id bands and thinking about switching to 16mm for more power, anyone have experience with that setup?
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Old 03-05-2019, 02:51 AM   #2
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Re: Band width for carbon gun

If you are using 7.5mm shaft or heavier, you would do better with 2 x 14.5mm to 15mm small ID bands stretched at high stretch. If using 7mm shaft or less then just remove one of your 14mm small ID bands and get your stretch to around 370%. You certainly will not get more power by switching to 16mm bands. Best performance is having just the right amount of band power where your shaft can absorb it fully ... more than that and you get an unstable shaft ... and thus much less performance as an unstable shaft loses velocity very quickly.
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Old 03-05-2019, 08:08 PM   #3
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Re: Band width for carbon gun

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Originally Posted by spearq8 View Post
If you are using 7.5mm shaft or heavier, you would do better with 2 x 14.5mm to 15mm small ID bands stretched at high stretch. If using 7mm shaft or less then just remove one of your 14mm small ID bands and get your stretch to around 370%. You certainly will not get more power by switching to 16mm bands. Best performance is having just the right amount of band power where your shaft can absorb it fully ... more than that and you get an unstable shaft ... and thus much less performance as an unstable shaft loses velocity very quickly.
Why would 2 bands be better that 3?
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Old 03-06-2019, 06:22 AM   #4
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Re: Band width for carbon gun

The thinking is that a thinner shaft can't take a whole lot of power before it starts buckling and whipping - and once that happens, you have in effect overpowered it leading to less accuracy, less speed and less penetration.
SpearQ8 has spent months testing numerous setups in his pool hence the specific advice about how much power (thickness and number of bands and their stretch) each thickness of shaft can take.
You could easily test his advice by dropping one band and then comparing it to what you have now - and if you have bought 16mm rubbers you could compare to those, too.
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Old 03-06-2019, 07:54 PM   #5
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Re: Band width for carbon gun

what diameter and length shaft Ben?
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Old 03-07-2019, 03:06 AM   #6
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Re: Band width for carbon gun

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Why would 2 bands be better that 3?
Actually that is a good question and I am not really sure I know exactly why that happens as it is counter intuitive. But I think it is similar to throwing a paper airplane where too much force applied to throw the airplane can cause destabilization of flight and thus additional power will work against it. Much better is a smooth release with just the right amount of power. There is a point where if you put more power than the mass of shaft can absorb, the additional power will work against you. Best is to have the maximum amount of band power that a shaft can absorb where it will still keep the shaft stable. Also a stable shaft is dramatically more accurate.

In this video you can see some of this happening. I use 2 x 14.6mm small ID bands at very high 380% stretch on a 7mm shaft and then I use 2 x 14mm small ID bands at a lower stretch 360% ... and the 14mm small ID bands have more power. I then use an 8mm shaft and things are reversed where the 8mm shaft is able to absorb the additional band power without losing stability and thus the 2 x 14.6mm bands at high stretch perform much better. I have also done this with 3 x 16mm bands vs. 2 x 14mm bands on 7mm shaft and the 2 x 14mm had more power.

For 7.2mm shafts and lighter ... best is 2 x 14mm ... even 13.7 mm small ID bands if you can find them

For 7.5mm shafts best is 2 x 14.5mm to 15mm small ID bands at high stretch

For 8mm ... maybe 2 x 14.5mm to 15mm small ID bands at high stretch will give you good results but an extra band will improve things a little

For 8.5mm or heavier ... have to go 3 x 14.5 to 15mm small ID with the highest stretch you can load

This all assumes about 120cm or more of band stretch and is not an exact science but rather ball park figures.

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Old 03-07-2019, 01:08 PM   #7
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Re: Band width for carbon gun

I never shot that particular gun, but I've played around with different band set ups a bit.

14.5mm small ID is a great balance when it comes to bands. Easy to pull back, you can load at Higher Stretch, this allows a Shorter Band length which means less mass flying around as the shaft is exiting the gun, i.e. less recoil. Recoil and specifically Felt Recoil is more complicated than just the mass of the shaft exiting the gun at it's speed. Smaller Diamter bands like 13-14mm tend to fly around like a birds nest after the shot and move around the front of the muzzle. 14.5mm and thicker tend to stay put especially if they are held firm in the muzzle. There's more to shaft stability than the power on the shaft, much of it is the power on the gun.. if the gun is getting jerked around, it's tough to keep the shaft stable.

Think about this. 3 Regular ID 5/8" Bands at 340% Stretch might measure 30" each. That's 90" of bands moving around in an agitated state. If you can replace those with 2 Small ID 14.5mm bands at 370% they might measure 27" each That's only 54" of smaller diameter bands moving around.. much less disturbance to the platform.

Back to the original question. 3 x 16mm small ID Bands are a bear to load at higher stretch. They have a different Kick than 14.5mm. In my experience more explosive. But on the right platform, 16mm bands replacing 14.5mm can offer more power/ie range. 2 16mm Small Id bands on a 5/16" Shaft can be a good combination at @ 360%. But 3 small ID 16mm on a 5/16" you would need to have a fairly heavy gun to offset all of that mass flying around. Essentially you would be replacing 4 14.5mm small ID bands with 3 x 16mm. But.. struggling more with each band. We also did some mix band experiments. 14.5mm mixed with 16mm. That might be something for you to try. Use 1 16mm and 2 14.5mm
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Old 03-07-2019, 02:31 PM   #8
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Re: Band width for carbon gun

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Originally Posted by kavachi View Post
what diameter and length shaft Ben?
My Mori slip-tip is 160mm (tip to tail) * 7.5mm.
Band slot to notch is about 130mm on average.
Bands are 24' plus 3.5' wishbone.
(Never figured out why we measure the shaft in metric and the bands in inches )....anyway, that's how it's currently set up.
The 3 bands are 14.5 small id from Spear America.

My past guns I have always preferred the 16mm bands, but it shoots well in this configuration as well.
I just want to maximize the efficiency so if you guys have advice for optimal set up I am all ears.

Thanks
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Old 03-07-2019, 10:35 PM   #9
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Re: Band width for carbon gun

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Originally Posted by BenGreen View Post
My Mori slip-tip is 160mm (tip to tail) * 7.5mm.
Band slot to notch is about 130mm on average.
Bands are 24' plus 3.5' wishbone.
(Never figured out why we measure the shaft in metric and the bands in inches )....anyway, that's how it's currently set up.
The 3 bands are 14.5 small id from Spear America.
My past guns I have always preferred the 16mm bands, but it shoots well in this configuration as well.
I just want to maximize the efficiency so if you guys have advice for optimal set up I am all ears.
Thanks
some great advice there from Jon and Majd

I havent shot that gun either but going from experience with that shaft [been my go-to size for ever] and bandstretch on my own wood guns, running 3 x 14.5mm Primeline small ID bands is a serious amount of grunt for that shaft.

Being a lazy prick i stick with two bands whenever i can, and have found twin 14.8mm [what the Benthic 15mm rubber calipers at] small ID tied at 380% throws that shaft nicely even on longer shots.

always looking to pack as much punch into the package i can, i've found shortening up the bridles to two inches [5 or 6 cm] rubber-end to rubber-end not only adds a little more stretch, but also makes loading onto the rear tabs a little easier too.

If I'm caught in Doggie country or out the FADs with only this two band gun, I'll swap the bands for twin 16mm small ID at 380%. These 16mm small ID do take a bit more effort loading than the 15s, but with forward loading tab on the Hunt shafts, and a comfy loading pad, there's no gut-busting required. Much preferable to the hassle of a third band IMHO.
I DONT use the 16mm bands for normal reef hunting tho, too much work excavating shaft from reef, the 14.5 or 15mm are just right

Only time i use three bands is with 3 x 16mm smallID on my 145 bandstretch Doggie gun throwing a heavy 8.5mm double flopper shaft [not the sort of gun you're reloading every few minutes]. and the range and penetration with three bands is really something to behold. The dense wood guns really come into their own for this work, compact footprint but heaps of mass to soak up that recoil.
Have a sticky at Majd's Youtube videos testing his Albacore with 3 x 15mm bands, serious Doggie weapon.

those dimensions youve provided dont quite stack up - sticking with metric 61cm of rubber over 130cm bandstretch is 425% in spearo terms. i have tied and shot small ID bands at that stretch and they go great, but die pretty quickly. I am tying at 380% new, and ending up at 400% after a couple of reties, thats the sweet spot for me

if thats you in your profile pic [bloody nice fish by the way!] i dont think loading hot 15 or 16mm small ID bands will be an issue, but whether 7.5mm shaft can usefully absorb any more power on that platform than youve already got........need to test that out in the water

Last edited by kavachi; 03-07-2019 at 10:59 PM.
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Old 03-08-2019, 12:05 AM   #10
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Re: Band width for carbon gun

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Originally Posted by kavachi View Post
some great advice there from Jon and Majd

I havent shot that gun either but going from experience with that shaft [been my go-to size for ever] and bandstretch on my own wood guns, running 3 x 14.5mm Primeline small ID bands is a serious amount of grunt for that shaft.

Being a lazy prick i stick with two bands whenever i can, and have found twin 14.8mm [what the Benthic 15mm rubber calipers at] small ID tied at 380% throws that shaft nicely even on longer shots.

always looking to pack as much punch into the package i can, i've found shortening up the bridles to two inches [5 or 6 cm] rubber-end to rubber-end not only adds a little more stretch, but also makes loading onto the rear tabs a little easier too.

If I'm caught in Doggie country or out the FADs with only this two band gun, I'll swap the bands for twin 16mm small ID at 380%. These 16mm small ID do take a bit more effort loading than the 15s, but with forward loading tab on the Hunt shafts, and a comfy loading pad, there's no gut-busting required. Much preferable to the hassle of a third band IMHO.
I DONT use the 16mm bands for normal reef hunting tho, too much work excavating shaft from reef, the 14.5 or 15mm are just right

Only time i use three bands is with 3 x 16mm smallID on my 145 bandstretch Doggie gun throwing a heavy 8.5mm double flopper shaft [not the sort of gun you're reloading every few minutes]. and the range and penetration with three bands is really something to behold. The dense wood guns really come into their own for this work, compact footprint but heaps of mass to soak up that recoil.
Have a sticky at Majd's Youtube videos testing his Albacore with 3 x 15mm bands, serious Doggie weapon.

those dimensions youve provided dont quite stack up - sticking with metric 61cm of rubber over 130cm bandstretch is 425% in spearo terms. i have tied and shot small ID bands at that stretch and they go great, but die pretty quickly. I am tying at 380% new, and ending up at 400% after a couple of reties, thats the sweet spot for me

if thats you in your profile pic [bloody nice fish by the way!] i dont think loading hot 15 or 16mm small ID bands will be an issue, but whether 7.5mm shaft can usefully absorb any more power on that platform than youve already got........need to test that out in the water
Thanks for the advice and yeah that's me with a 50# White Seabass that I ironically took down with a 90cm cheap Mako speargun coming up from underneath, go figure. I don't do much reef hunting, mostly kelp forest and I like POWER, but also accuracy. The 3 * 15mm setup sounds promising, what band stretch? Also, where do you guys get your rubber? I definitely need to dedicate more time experimenting with the various configurations
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Old 03-08-2019, 12:11 AM   #11
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Band width for carbon gun

Quote:
Originally Posted by BenGreen View Post
Thanks for the advice and yeah that's me with a 50# White Seabass that I ironically took down with a 90cm cheap Mako speargun coming up from underneath, go figure. I don't do much reef hunting, mostly kelp forest and I like POWER, but also accuracy. The 3 * 15mm setup sounds promising, what band stretch? Also, where do you guys get your rubber? I definitely need to dedicate more time experimenting with the various configurations


Spearamerica has it at good prices (I think around $2.25/feet for 14mm). Benthic should have it to. I think both will put a caliper on their stock for you and check that you get what you want, at least Spearamerica will. The batches can vary a bit in real sizes.
[EDIT} Just checked both sites and seems like Benthic might have a wider selection as of writing this. E.g. you can get small ID in pink now, yihaa!


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Old 03-08-2019, 12:29 AM   #12
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Re: Band width for carbon gun

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Originally Posted by kavachi View Post
some great advice there from Jon and Majd
those dimensions youve provided dont quite stack up - sticking with metric 61cm of rubber over 130cm bandstretch is 425% in spearo terms. i have tied and shot small ID bands at that stretch and they go great, but die pretty quickly. I am tying at 380% new, and ending up at 400% after a couple of reties, thats the sweet spot for me
With a 3.5 inch wishbone I believe it comes out 375% or thereabouts, or am I getting this wrong?
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Old 03-08-2019, 04:16 PM   #13
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Re: Band width for carbon gun

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Originally Posted by BenGreen View Post
With a 3.5 inch wishbone I believe it comes out 375% or thereabouts, or am I getting this wrong?
common practice to ignore the bridle when working out bandstretch

Distance from band slot to shaft tab multiplied by 2, divided by cut rubber length laid on flat surface. So yeah - your bands around 370%

pink small ID primeline?!! my daughters are gonna love that

Last edited by kavachi; 03-08-2019 at 05:02 PM.
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Old 03-08-2019, 08:59 PM   #14
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Band width for carbon gun

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pink small ID primeline?!! my daughters are gonna love that

Yeah, I just wish they came in 13mm, too.
I made a 90 pipe gun for a female friend a while back and also just shot another 90 a few weeks back - also meant for a beginner female spearo. Both were rigged with 2 x 13mm small ID and both were a joy to shoot and load. The precision of that latter one was just amazing - everyone who shot it could shoot it accurately. I guess there's something to be said for not over powering shafts;-). That said, it had enough power for securing plenty of dinner fish for us and when a curious 15kg GT came in, my friend took that one, too.



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Old 03-08-2019, 11:23 PM   #15
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Re: Band width for carbon gun

Looks like all the colors of the rainbow are available, now that purple stock and fluoro-lime green grip handle speargun with pink bands can become a reality!

All it would need would be a rose gold spear to finish it off.
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