Inner Barrel Muzzle Threads and Sizes

[popgun pete]

We have had threads on hand pump screw thread sizes, maybe we could do with one on muzzle screw thread sizes seeing as many people are looking to swap muzzles on their pneumatic spearguns. That said I must measure a few of mine while their muzzles are removed. More later.

 

[istriker22]

Good idea. I just asked a question on a different thread regarding this (Salvimar muzzle to Cyrano)


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[popgun pete]

Good idea. I just asked a question on a different thread regarding this (Salvimar muzzle to Cyrano)


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Salvimar make a version of it for 11 mm inner barrels, they don't have a gun that size themselves (yet!) so I would think it was for the Mares gun. Check the advert for the kit, from memory there are a number of versions for different guns in the rear handle, full length tank format.

In fact look here: http://forums.deeperblue.com/threads/salvimar-vacuum-barrel-kit.98453/

 

[Jegwan]

Great idea Peter. I think we should add information of the length of the thread entering the muzzle.
Jégwan

 

[istriker22]

Salvimar make a version of it for 11 mm inner barrels, they don't have a gun that size themselves (yet!) so I would think it was for the Mares gun. Check the advert for the kit, from memory there are a number of versions for different guns in the rear handle, full length tank format.

In fact look here: http://forums.deeperblue.com/threads/salvimar-vacuum-barrel-kit.98453/

Thank you Pete! I used the Mares airguns again this weekend and was very impressed. I had forgotten how hard these guns shoot!

 

[popgun pete]

I measured these guns, the thread length "L" is that on the front end of the inner barrel, the metric thread form and the diameters of the inner barrel tubing. Second number on thread designation is pitch, or spacing between adjacent thread peaks.

Mares "Sten" OD 18 mm, ID 13 mm, M18 x 1.25, L 1.87 cm
Mares "Cyrano" OD 16 mm, ID 11 mm, M16 x 1.25, L 1.8 cm
Technisub "Grinta" OD 17 mm, ID 13 mm, M17 x 1.25, L 2.3 cm
GSD "Katiuscia" OD 18 mm, ID 14 mm, M18 x 1.25, L 3.0 cm

 

[popgun pete]

I hope others contribute the numbers for guns like the "Airbalete", "One Air" and other models as I don't have those guns. Also the new "Cyrano Evo", although I suspect that it will be the same as the "Cyrano". The "Airbalete 12" or "Airbalete XII" is another new gun which will have a new size inner barrel tube. For the pitch just count the number of threads, measure the length of that threaded section and then divide that by the number of threads and you will have the pitch number.

 

[tromic]

From Italian forum:
http://apneaepesca.forumfree.it/?t=64980527

 

[popgun pete]

From Italian forum:
http://apneaepesca.forumfree.it/?t=64980527

Tomislav, as you are making the muzzle vacuum barrel kits then you must know the various muzzle thread sizes, so why not put them down here so that we can see them all in one place? Rather than jumping around looking at posts on various other forums.

 

[Jegwan]

I will put mine down here.. just need a little time.. the guns are pressurised and ready for hunting
Here's the first ones:

Technisub "Drago" OD 17 mm, ID 13 mm, M17 x 1.25, L(m) 2.65 cm (forward latching muzzle)
Mares "Vicojet" OD 18 mm, ID 13 mm, M18 x 1.25, L(m) 1.25 cm

I hope I understood your definition of L correct. My L(m) is the length of the thread on the inner barrel entering the muzzle.

Jégwan

 

[popgun pete]

The inner barrels were out of the guns, so the "L" that I measured is just the length of the screw thread on the nose of the tubing. Generally the guns are made so that with everything done up correctly the inner barrel front end is just rearwards of the ring of the relief port openings in the muzzle. Sometimes you can have a gun where the end of the inner barrel tube is just starting to show in the relief ports, that usually indicates that the rear end of the inner barrel tube is not fully snugged up in the rear handle moulding when the inlet valve body was screwed into place.

 

[Jegwan]

Yes. The length of the thread entering the muzzle can vary a tiny bit on the same gun model - but it varies between the gun models. It might be necessary to use a spacer (in nylon or so) or to shorten a muzzle if you exchange muzzles on various gun models.

The Salvimar Vuoto fit's on the inner barrel thread of both the Mirage and the earlier Stens - but I believe that you will need a spacer (or a shorter shock absorber) to make the muzzle and front cone vacuum seal - and not "lock" the shock absorber in the muzzle.

Jégwan

 

[popgun pete]

My Scubapro "Magnum" is still under pressure, but as the Salvimar "Vintair" and "Vuoto-Air" are its near identical twins, then it should have the same thread form on the nose of its inner barrel. I was never able to undo its muzzle, even with the inner barrel out of the gun as it appeared to be staked through one of the relief ports (a punch was used to squash the thread form as the barrel nose slightly enters the port). I disassembled it working from the rear end instead. Interestingly it was lubricated inside with grease, not one drop of oil, although now it has oil inside it. My thoughts were the early "Magnum" guns were not oil lubricated and the muzzle was deliberately staked to prevent you undoing it. The stainless steel shock absorber anvil goes in from the rear as the muzzle body is one-piece and consequently is a bit shorter than usual, i.e. it has no nose cap.

 

[Jegwan]

That's interesting and very good to know if you are going to take a "Magnum" apart. The Salvimar Vuoto air and Ventair muzzle are a similar type without nose cap - like the Sten 11.

I suppose that you have used it for years with only grease inside - was everything greased or was it only the moving parts?

I changed the "L" to "L(m)" in my previous post. So:
L = Length of thread on inner barrel
L(m) = Length of thread entering the muzzle.

I will ask my body if we can take the pressure and muzzle of his Vuoto air and measure the thread - you're probably right, that's it identical to the Scubapro "Magnum".

Jégwan

 

[tromic]

Pete, I actually just did Tomba vacuum barrel design. I suppose Marko has some data more, but also not for all types of spear guns, especially not for the newest.

Mares "Sten" OD 18 mm, ID 13 mm, M18 x 1.25, L 1.87 cm
Mares "Cyrano" OD 16 mm, ID 11 mm, M16 x 1.25, L 1.8 cm
Mares "Vicojet" OD 18 mm, ID 13 mm, M18 x 1.25, L(m) 1.25 cm
Mares Cyrano Evo HF: OD 16 mm, ID 11 mm, M16 x 1.25, L(m) 1.7 cm (thread in muzzle, on barrel might be 1,8 cm)
Technisub "Grinta" OD 17 mm, ID 13 mm, M17 x 1.25, L 2.3 cm
Technisub "Drago" OD 17 mm, ID 13 mm, M17 x 1.25, L(m) 2.65 cm (forward latching muzzle)
GSD "Katiuscia" OD 18 mm, ID 14 mm, M18 x 1.25, L 3.0 cm

 

[zmajmr]

Omer Airbalete M16 x 1.5 , ID = 11 mm I guess, I did not measure so I do not have exact number , L= (39.6 - 12.4 )= 27.2mm , so thread begins after 12.4 mm of flat part with no thread, there is step in side of muzzle, conclusion you can not change it with some other muzzle

Mares Cyrano Evo HF , similar as Airbalete design, you can not change it with other muzzle, M16 x 1.25 , L= (49.75 - 33) = 16.75 mm , also step design muzzle, not simple as regular Mares Cyrano

Mares "Sten 11" M16 x 1.25, ID = 11 mm, L = 17.4 mm

Mares Jet M18 x 1.25 , ID = 13 mm, L = 18.85 mm, there is M18 but actually it is OD = 17.75, similar to other guns where it is M18

Mares Bazooka M18 x 1.25, ID = 13 mm, L = 20 mm

Cressi SL M16 x 1.25, ID = 13 mm, L = 16.6 mm, L is how deep there is thread in muzzle if we measure from edge where it begins

Seac Asso M18 x 1.5, ID = 13 mm, L = 18 mm

Seac Caccia M 16 x 1.5 , ID = I guess it is 11 mm, I do not have gun, L = 18 mm

Mares Mirage M18 x 1.25, ID = 13 mm, L = 22 mm


Mares Mirage, Mares "Sten 13" and Mares Jet have muzzles that can be changed between them.

 

[popgun pete]

Very good information which adds to the list, I think this covers most of the guns now in common use. It will be interesting to learn if there are any others. It would be possible to put a vacuum muzzle on mid-handle pneumatic guns, but few spearfishermen seem to use them these days in the ocean.

 

[popgun pete]

That's interesting and very good to know if you are going to take a "Magnum" apart. The Salvimar Vuoto air and Ventair muzzle are a similar type without nose cap - like the Sten 11.

I suppose that you have used it for years with only grease inside - was everything greased or was it only the moving parts?

I changed the "L" to "L(m)" in my previous post. So:
L = Length of thread on inner barrel
L(m) = Length of thread entering the muzzle.

I will ask my body if we can take the pressure and muzzle of his Vuoto air and measure the thread - you're probably right, that's it identical to the Scubapro "Magnum".

Jégwan

I changed it to oil lubrication not long after I purchased it as it had a micro-leak at the rear tank "O" ring which put an oily bloom on the tank surface, but it was a very slow leak that took a long time to affect the pressure in the gun. A small cut on the "O" ring periphery was responsible, only visible when inspected with a strong magnifier as otherwise I would have missed it. I never got the muzzle off as to do so I would have had to put a drill down the affected relief port and remove the flattened thread section. That is what I will do if I ever want to change the muzzle, but the gun shoots OK as is and I have shot many fish with it.

 

[popgun pete]

The "Seabear" or "Pyrometer/Orion" has a muzzle with thread M16 x 1 cut into its stainless steel inner barrel tube, most of that barrel being exposed in what is a classic mid-handle pneumatic speargun layout with the air tank situated at the rear. A "Seabear" is much like a Nemrod "Clipper", only of all-metal construction bar the hard grip scales on the uncomfortable slim handle. The length "L" of exposed screw thread with the alloy muzzle removed is 13 mm. The "Seabear" alloy muzzle is one-piece (with only three muzzle relief ports) and is not loaded up by the air pressure acting on a bulkhead as it is on rear handle pneumatic guns because the front pressure bulkhead in the "Seabear" is located in the handgrip section. It seems to me that "Seabear" guns could easily be equipped with a vacuum muzzle that also contained a shock absorber as then one could eliminate the polyurethane bush on the "Seabear" piston and replace the entire unit with a Mares piston as both guns use 13 mm ID inner barrels. "Seabear" users are stranded if their gun's piston loses its shock absorber, but the gun could use a move conventional muzzle and then just replace the existing spear tails to suit the new form of piston. Could be a business proposition for someone to offer retrofit muzzles and pistons, or an adaptor to use something else, like the Salvimar vacuum kit muzzle on the many "Seabear" guns in the USA.

N.B. I recently replaced my "Seabear" piston's polyurethane bush, the previous bush disintegrated just from continual pressure ramming it onto the muzzle's travel stop. It is easy to do if you put the piston tail or shank section in a drill press chuck and then push the piston down onto a level block of wood supporting the new polyurethane bush by pulling the drill press control lever down. This action forces the bush squarely onto the piston nose which is otherwise not very easy to do.

 

[zmajmr]

Now I remembered one more info:

Tigulio Ras is compatible with muzzle from Mares Sten with 13 mm piston