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All About Guns What's your weapon of choice, and why? Discuss the beloved speargun here!

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Old 09-06-2019, 07:46 AM   #16
ninjagazz
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Re: Spearguns for Dogtooth Tuna

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Originally Posted by Diving Gecko View Post
Hey Gazz,
I would be remiss if I didn't throw a curve ball in here
Thing is, you have some pretty long vacuum muzzled airguns, don't you? I have been shooting smaller DTs on a recent trip with one of my pneumatics but you need a heavier shaft.
I shot a 145cm 8mm shaft and though the biggest DT I shot was around 10kg, I have no doubt that with enough pressure in the gun that shaft would be fine for a DT at least 2-3 times bigger.
But here's the catch, I don't think that the pressures we can load our traditional airguns at in a single stage/stroke is enough to power these heavier shafts to the speed needed for DT hunting. So, you need to "cheat" and use something like a Tomba Easy Loader or possibly my own contraption - The Pulley Loader.

I know they might look cumbersome but the pulley loader was actually easier to use than I thought it would be. It does take a little while longer to load a gun with it than a two-banded gun, so that's a downside. But as I said, just a curve ball idea

Hi Gecko, it has been a while.

I have a salvimar predathor vuoto 130, with race kit and power reducer removed for the trip. This gun was setup with the idea for the reef, but i think it will be a good doggie gun. I don't know which gun is more powerful the airgun or triple rubber. Keen to do some target practice and find out. loading the 130 is easier than most people realise.

I have a 7.14 spear and 8.15 spear (strange size) both 150cm for this gun and some others stuck in customs. Nervous about loosing the long spears for the pneumo as they are had to come by hear on Aus.

Which airgun are you using Gecko?
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Old 09-06-2019, 08:12 AM   #17
Diving Gecko
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Re: Spearguns for Dogtooth Tuna

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Originally Posted by ninjagazz View Post
Hi Gecko, it has been a while.

I have a salvimar predathor vuoto 130, with race kit and power reducer removed for the trip. This gun was setup with the idea for the reef, but i think it will be a good doggie gun. I don't know which gun is more powerful the airgun or triple rubber. Keen to do some target practice and find out. loading the 130 is easier than most people realise.

I have a 7.14 spear and 8.15 spear (strange size) both 150cm for this gun and some others stuck in customs. Nervous about loosing the long spears for the pneumo as they are had to come by hear on Aus.

Which airgun are you using Gecko?
Yep, been a while but good to hear you didn't give up on the oleos.
I got obsessed with the Mirage style guns and have been buying a few of these oldies and then upgrading them. They are getting really old and weren't that well-designed from the get go, so just keeping them leak-free has been a challenge.
But the main reason for sticking with them is that they offer a way to load the gun at higher pressures than normal. For most of my 13mm piston airguns, I can't really load them at over 22bar, but I can load a Mirage at 30-33bar without too much trouble.
Think of a Mirage as a multi-stage loading gun while your Predathor is a single stage gun. It's like putting more bands on a band gun splits up the loading effort and allows a higher total energy to be stored than if it was all just one fat rubber. That's what I can do with my Mirages.

For the vast majority of hunting, a single stage, traditional airgun is fine and I find that it powers up 7mm shafts plenty well. But I feel like 20-25 bar is a bit low for 7.5mm shafts and 8mm shafts ideally need more power - which is why I am still trying to make the Mirage guns work.
On that note, my lastest Mirage is based on a Predathor barrel for a Predathor 130, so I am shooting the same length of shafts as you, more or less, at 7.5mm and 8mm but the gun sits around 30 bar. The next one, I want to get to +35 bar and start shooting 8.5mm shafts.

Here's a few pics of the gun:



Actually, I ended up pulling the bulkhead out of my gun, too as I had issues with some built-in check valves. At that point, it was back to being a single stage loading gun like yours - but I was still able to load it at around 30 bar with the help of the Pulley Loader, I linked to earlier:





And here's a crazy long build thread of my endeavors incorporating 3d printing to make functional parts like nose cones and power regulator bulkheads.

Oh, bugger... I just realize you have the Vuoto muzzle on your gun. I have had issues with the shock absorber in that design when going over 25 bar, so probably best not to try a pulley loader on a gun with a Vuoto muzzle. But good that you pulled out the power regulator bulkhead, that should help.
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Old 09-06-2019, 08:43 AM   #18
ninjagazz
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Re: Spearguns for Dogtooth Tuna

Gecko, Your airgun is just ...WOW!

Any videos?

My "115 vuoto predathor" shoots the 8mm spear nicely but not as fast as the 7mm.

When I pulled apart the 130 i found there were 3 orings sealing the handle to the outer barrel rather than the normal single.
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Old 09-06-2019, 09:17 AM   #19
Diving Gecko
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Re: Spearguns for Dogtooth Tuna

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Originally Posted by ninjagazz View Post
Gecko, Your airgun is just ...WOW!

Any videos?

My "115 vuoto predathor" shoots the 8mm spear nicely but not as fast as the 7mm.

When I pulled apart the 130 i found there were 3 orings sealing the handle to the outer barrel rather than the normal single.
Not much video. Though I shot a lot, I didn't get around to editing. I only uploaded two short clips for the threads over at DB as a bit of a payoff to the people who had taken an interest in the build.
One here shows a DT wiggling off the shaft after it had decided to close the barb... (8mm shaft, 29bar):
https://forums.deeperblue.com/thread...13#post-983679

And a shot I wouldn't take on a much bigger fish but I kebab'ed this one from the rear (8mm shaft, 28bar):
https://forums.deeperblue.com/thread...2/#post-984215

You mean, three main seals apart from the bulkhead? Yeah, I have seen Predathor nose cones with both one and two o-rings. In my own designs, I go for double seals whenever possible. Just for peace of mind. Oh, and thanks for the nice words - it's just me having too much time on my hands and liking a challenge;-)

Last edited by Diving Gecko; 09-06-2019 at 09:31 AM.
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Old 09-06-2019, 03:08 PM   #20
popgun pete
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Re: Spearguns for Dogtooth Tuna

When a "Mirage" worked properly it can shoot an 8 mm shaft with 40 bar start pressure, the main problem was the bad internal breathing of the gun works like a throttle and robs the gun of the power that it should have. A "Sten" can be used at 40 bar, but is near impossible to load without standing on something, I have done it more than once (metal piston gun, not the later plastic version). Shots are very powerful and fast, but for a practical 40 bar gun you need a loading system as DG says, either a pulley/winching system or a better breathing "Mirage" with its gas transfer secondary pumping barrel, which is what DG's black and red creation is.

Mares had a go at revamping the "Mirage" with a slightly better regulator block that holds the pumping barrel, but never fixed the air passages in the rear handle which strangle the gun, and then they gave up. DG's gun uses the Cyrano nee Evo handle and builds on its better airflow, something that Mares could have done themselves. Possibly all their best men have retired and all the product decisions are now made by bean counters. How much money they ever made on the "Mirage" sales and the nightmare assembly of the guns with their many "O" rings may have been a factor in not making a "Mirage Evo".

There are 100 bar guns such as the "Black Sea" auxiliary hydropump hydropneumatic guns, they don't float, but are super powerful. They can be used on Doggies, but you are looking at a grand or more of gun disappearing on you if you lose it to the depths, plus for now they are no longer made. Replete with titanium and stainless steel to stop them blowing to pieces you find that you have a problem if air travel requires them to be depressurized. Regulations do require it, but will anybody know different as there is no way to check? That is why transporting the 100 bar guns is problematic. At least with a standard pneumatic the hand pump is not very big and is easily transported as pumping to 40 bar is about a half hours work allowing short rests and the hand pump to cool down briefly.

Third photo shows a buoyancy jacketed "Black Sea" (not my gun) that was tricked up by the owner.
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Last edited by popgun pete; 09-06-2019 at 03:32 PM.
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Old 09-06-2019, 04:28 PM   #21
popgun pete
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Re: Spearguns for Dogtooth Tuna

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Originally Posted by Diving Gecko View Post
Not much video. Though I shot a lot, I didn't get around to editing. I only uploaded two short clips for the threads over at DB as a bit of a payoff to the people who had taken an interest in the build.
One here shows a DT wiggling off the shaft after it had decided to close the barb... (8mm shaft, 29bar):
https://forums.deeperblue.com/thread...13#post-983679

And a shot I wouldn't take on a much bigger fish but I kebab'ed this one from the rear (8mm shaft, 28bar):
https://forums.deeperblue.com/thread...2/#post-984215

You mean, three main seals apart from the bulkhead? Yeah, I have seen Predathor nose cones with both one and two o-rings. In my own designs, I go for double seals whenever possible. Just for peace of mind. Oh, and thanks for the nice words - it's just me having too much time on my hands and liking a challenge;-)
If the manufacturer thinks the ends of the gun may banana they install more body rings to improve sealing and mechanically resist the tendency for the parts to cant over slightly inside the body tube. In the distant past when cost cutting was not a consideration the overlap sections were longer with a lot more length to the bosses on which the "O" rings are mounted. In the eighties bosses were shortened and were taken to the bare minimum, however those guns really went like a banana under pressurization, so the bosses were lengthened again, but well short of what they had been in the past.
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Old 09-08-2019, 07:54 AM   #22
ninjagazz
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Re: Spearguns for Dogtooth Tuna

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Originally Posted by Diving Gecko View Post
Not much video. Though I shot a lot, I didn't get around to editing. I only uploaded two short clips for the threads over at DB as a bit of a payoff to the people who had taken an interest in the build.

You mean, three main seals apart from the bulkhead? Yeah, I have seen Predathor nose cones with both one and two o-rings. In my own designs, I go for double seals whenever possible. Just for peace of mind. Oh, and thanks for the nice words - it's just me having too much time on my hands and liking a challenge;-)
I appreciate the videos and i am amazed at the power of the dogtooth tuna!

What sort of effective range are you seeing from the airgun? How far away are you shooting the fish from the end of your speargun?

Also how long is your floatline?

I need to spend a bit of time catching up on some of your more recent threads, the Mirage project sounds fascinating.
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Old 09-08-2019, 10:34 AM   #23
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Re: Spearguns for Dogtooth Tuna

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I appreciate the videos and i am amazed at the power of the dogtooth tuna!

What sort of effective range are you seeing from the airgun? How far away are you shooting the fish from the end of your speargun?

Also how long is your floatline?

I need to spend a bit of time catching up on some of your more recent threads, the Mirage project sounds fascinating.
As for the general rigging/float line questions, others here are the real masters and there are amazing knowledge to be found in other threads. I learned a lot there.

That said, for shooting line, I used crimped, stiff dyneema and my floatline is a 25m DIY one. It's nice and slim at just Ř6mm OD (I'd rather not ever have to swim around with something like a half inch Riffe - no idea why it has taken so long for manufacturers to start making slim lines).
If we were diving in a bit shallower spots, I could shorten the line accordingly. The whole idea is to not give DT a chance to get to the bottom.

I only had 31L of floats (20L + 11L RA floats) and yes, it's nuts how even a small 10kg DT can pull down +20L of floats like it was nothing. My friend's 20kg fish took down a 25L float for perhaps 3 mins and dragged it about 200m underwater before it popped back up (fish still on).

Not sure about the range of my gun and I haven't done any penetration tests on foam with it. But I have three wraps on it and it tugs nicely at the end of them. I'd say, the DT I took were medium to long shots. I don't think anything was under 3m. For a few years, I have been wanting to compare my Mirage to a Denton 120 as that gun is such a known benchmark, but haven't gotten around to it, yet.
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Old 09-08-2019, 03:49 PM   #24
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Re: Spearguns for Dogtooth Tuna

A pneumatic will do anything a band gun can, the problem is loading it which has always been their limitation as basically you do it all in one go (the “Mirage” excepted). Band guns have always had the edge in slapping on more bands and splitting the loading effort, if you can load one band then you can do multiples thereof and the effect is cumulative. Plus you can customize and make changes by drilling holes in it and reconfiguring it in the case of a timber gun and you don't have to worry about denting it, although pneumatic guns can survive a few dents (some of my guns), but it is not ideal.

Last edited by popgun pete; 09-09-2019 at 03:35 PM. Reason: left out the "can"
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Old 09-08-2019, 07:14 PM   #25
ninjagazz
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Re: Spearguns for Dogtooth Tuna

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A pneumatic will do anything a band gun can, the problem is loading it which has always been their limitation as basically you do it all in one go (the “Mirage” excepted). Band guns have always had the edge in slapping on more bands and splitting the loading effort, if you load one band then you can do multiples thereof and the effect is cumulative. Plus you can customize and make changes by drilling holes in it and reconfiguring it in the case of a timber gun and you don't have to worry about denting it, although pneumatic guns can survive a few dents (some of my guns), but it is not ideal.
I agree Pete, but in my experience pneumatics are generally less reliable than a decent band gun. My salvimars go through the rubber dry barrel cuffs faster than i would like and the tangs on the shafts tend to deform and get stuck n the slide rings. (I prefer slide rings).

So I will have both. But i think the "salvimar hero" will be my primary gun for the sake of reliability.
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Old 09-08-2019, 08:32 PM   #26
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Re: Spearguns for Dogtooth Tuna

The shaft tails tend to hammer into the stop rings, you can turn the stop ring around, but have to unscrew the spear tail, unless you have screw on spear tip shafts. As for the vacuum cuffs getting damaged there is not much that be done about that, although some have tried a polyurethane sleeve for the stop ring to run into. That is intended to reduce sharp edges hammering up on the spear tail stop diameter as that is what catches on the vacuum cuff lip.

Here is a photo of the polyurethane spear tail stop.
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Old 09-08-2019, 09:07 PM   #27
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Re: Spearguns for Dogtooth Tuna

This is the latest "Taimen" spear tail with a polyurethane shaft tail stop. Originally developed for their rubber nozzle vacuum cuff which everyone has now copied, the polyurethane was molded directly onto the shaft and when the bush broke up you basically needed to replace the shaft as there was no easy way to renew the polyurethane bush. This replaceable version has only been around a short time so it has not been out in the field for very long, but it may be the answer to not tearing up vacuum cuffs and yet providing a strong line slide stop as it is more than a polyurethane bump on the shaft.
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Old 09-15-2019, 05:50 AM   #28
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Re: Spearguns for Dogtooth Tuna

Andre has a new inverter for the 8.5x1500 shaft. Very well balanced gun to land a reef or any size DTT. Practically no recoil. If you are going to order, contact them directly and ask for the Ermes trigger. You can also specify AR-15 handle instead of traditional wooden. Good luck.
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