Sten Competition Line or Sten 87 Model

[jimmy.k]

Hello guys, I recently purchased a vintage Mares speargun, the Competion Line Sten L 115 model, very similar to the recent Jet version but with some minor differences in the triggering system. Apparently this model has been discontinued as most companies have turned their marketing/production interest in the 11mm barrels and the faster 7mm shafts. Still a great gun however for the spearo enthousiast and a real legend when firstly introduced by Mares.

I have tried to perform the regular service before using the gun so I downloaded the Mares older service manual and purchased a fresh Jet/Sten oring set to change all the gaskets. Everything was pretty straightforward till I came across an o-ring that is no longer included in the new set. For some reason the trigger Oring with the code 46110213 is no longer included in the new oring set. The older o-ring installed in the gun eventhough it still worked had become stiff and unrecognizable so any chance to measure the dimensions was out of the question. I tried to replace the Oring with the small 46110242 included in the set which is used on most recent Mares trigger systems but after the first few pumps oil and air started to leak out from the trigger. I was very disappointed and thought at first that maybe I made a wrong choice in buying an older gun but I had to find a solution.

After a visit at the local Mares Dealer I was lucky enough to find their specialised technician who performs the service in the spearguns and scuba gear. I told him my story and complained all about the O-ring not included in the kit and the air/oil leak from the trigger. He said that the 46110213 o-ring was still available and used on other Mares Breathing Apparel so he gave me a handful to perform the service. I run home happy and after installing it the leakage stopped immediately. Mission complete.

What was funny, after completing the service, I read through the service manual again to make sure all the steps were completed correctly and BOOM on paragraph 29 the bloody answer was there the whole time...apparently Mares for the models with the snap fork triggering system replaces the 46110213 oring with the 46110201 which is the inlet valve Oring!!! This is why 2 of 46110201 are included in the set in the first place!!!

The question is..has anyone replaced the 46110213 oring with the 46110201 as the manual advises?? Does it work ??

For comparison purposes I have attached a photo of the 46110242 (left), 46110213 (center), 46110201 (right)

I wish to thank especially Popgun Pete for his valuable feedback and info he shared.

Happy dives everyone

 

[popgun pete]

The "Competition Line" model (Sten 87, which was slightly revised in 1989) was replaced in 2001 by a new "Sten" using the then current "Cyrano" handle. That "Sten" (2001) with the 13 mm inner barrel is still available, although you don't see it mentioned very often on the forums, but bear in mind a lot of spearfishermen never look at forums, hence that is no indicator of how many "Sten" guns are in use. By that time all "Cyrano" guns had switched to the 1.5 mm transmission pin, the original "Cyrano" had the thicker pin unless you purchased the "Apnea System" version of the "Cyrano".

I had to replace the trigger "O" ring in my “Miniministen” version of the "Competition Line" gun, but at the time the “O” ring kit had the correct "O" ring in the "Sten" kit as the 2001 "Sten" guns had yet to appear. The “O" ring that I took out had a tiny nick in it, was probably in there from new and the cut grew over time and with use and moved into the contact area with the pin.

 

[popgun pete]

Just to confuse everybody there is a "Sten 11" (the previous "Stealth" made under the Sporasub name when Mares owned Sporasub, then on sold to Omer). The "Sten" 13 mm gun is now joined by the "Cyrano 1.3" as well as a "Cyrano 1.1", the earlier "Cyrano Evo" (11 mm inner barrel) being given the boot.

 

[jimmy.k]

You are correct. In the Sten 2001 Series with the 13mm barrel their longest model was called the Super Sten and think it was 100 cm long. If I am correct Mares never produced any other model with the long barrel of the Sten L 115. Its a pain to find 8mm shafts over 100cm long nowadays. Mares has stopped producing them and are now only available from Seac (for the ASSO 115) and Devoto. Otherwise you need to make one by cutting a longer shaft from a rubber speargun.

 

[Diving Gecko]

Aha, the mystery of Mares o-rings and their naming...
I have spent countless hours trying to crack this nut and it's not always been much fun.
Below are my thoughts, but if you have a set of calipers please do measure your o-rings, too and report back.

46110242 should be an AS568-003 o-ring measuring 1.42mm x 1.53mm (ID x Cross Section). Or 4.48mm x 1.53mm (OD x CS).
Other references in Mares literature: There is a reference calling this ring for 2-003 which I think corresponds to the AS568-003 standard)
Usage: I think this one is now used for 1.5mm triggers in newer guns.

46110213 could be an AS568-004 o-ring measuring 1.78mm x 1.78mm (ID x Cross Section). Or 5.34mm x 1.78mm (OD x CS).
Other references in Mares literature: There is no direct '004' reference as in the example above but there is a reference to an 'O-ring 2007' which I think could possibly be to the Italian UNI standard of OR2007 which just so happens to be a 1.78x1.78mm ring).
Usage: Just looking at the numbers, and not knowing the diameter of the o-ring seat in your handle, this o-ring could make sense if your trigger pin was ø2mm, but I reckon yours might be ø3mm in which case it would be stretched quite a lot. That said, Mares were not always the most diligent in adhering to the best o-ring practices.

46110201 is the really weird one. I think it could originally have been an o-ring measuring 2.6mm x 1.9mm (ID x CS). Or 6.4mm x 1.9mm (OD x CS).
Other references in Mares literature: It is described as R/1 and OR-1 in various places and going out on a limb I speculate this could be a reference to a French standard.
Usage: With an ID of 2.6mm this would be a good candidate for a ø3mm trigger pin if the o-ring seat is designed accordingly. As you say, it also shows as the seal in the pump inlet valves.

Now, if you do indeed have a ø3mm trigger pin perhaps the following one would work, too:
46110101 which seems to be an AS568-006 o-ring with dimensions of 2.9mm x 1.78mm (ID x Cross Section). Or 6.46mm x 1.78mm (OD x CS). As you can see, it has very much the same OD as the one above though being of smaller CS will have a bit less compression on the pin.
Other references in Mares literature: Also called OR 2012 in many places which corresponds to the UNI again)
Usage: I've used this in pump inlet valves.

Finally, there's the little brother to the one just above:
AS568-005 o-ring measuring 2.57mm x 1.78mm (ID x Cross Section). Or 6.13mm x 1.78mm (OD x CS).
As far as I recall, I haven't seen this one in use in any of my Mares guns, though.

 

[Diving Gecko]

[EDIT] Its a pain to find 8mm shafts over 100cm long nowadays. Mares has stopped producing them and are now only available from Seac (for the ASSO 115) and Devoto. Otherwise you need to make one by cutting a longer shaft from a rubber speargun.

Look for Salvimar shafts. I have used Devoto before and while good, they are not that easy to source but Salvi makes 8mm airgun shafts up to 145cm long. I have about four of them and shot some nice fish on them.
This is the info from my latest order but please do double check yourself before ordering:
AIR TAHITIANA Ø8,0 SHAFT SINGLE BARB - 17-4PH, 8mm x 145cm, 907200/N, 8055960724284

Here are some screen shots from the Salvi catalogue. The red-green color coding is mine. I personally only like the 17-4PH shafts and would steer clear of the inox and zincata ones (I think the latter are the galvanized shafts and they are no good in vacuum muzzled guns).

You can download the catalogue here and go to page 96 for the same info.

 

[Diving Gecko]

You are correct. In the Sten 2001 Series with the 13mm barrel their longest model was called the Super Sten and think it was 100 cm long. If I am correct Mares never produced any other model with the long barrel of the Sten L 115.[EDIT]

As for long Stens, way back when (Pete should know) there used to be a 130 Super Sten, but may not have been made since the 80s.
In the past year or two, I have begun making long airguns from existing parts and it's true, you can't really source long Mares barrels any longer, but you can find Seac and Salvimar ones. The latter being by far the most affordable. None of them are a straight fit for Mares parts though, so they need a bit of modification.

 

[jimmy.k]

Appreciate all the great info, I made a research on o-ring measurements in metric and paid a visit at a store specializing in O-rings. I gave them a list with all the Mares Orings and they came with the following figures. I do not know the figures in Inch dimensions. Still missing the 213 which I did not have available at the time.There was a minimum quantity of 50 orings per type and but I paid like 25 euros for all of them, which is dissent as the service set costs around 9 to 12 euros at the local stores. They were not Viton though and I did not ask for their price which I presume should be considerably more.

46110242: 1,42 x 1,52mm
46110213: ?
46110201: 2,9 x 1,78mm
46110102: 6.75 x 1.78mm
46110107: 7.65 x 1.78mm
46110110: 9.25 x 1.78mm
46110227: 13.94 x 2.62mm
46110228: 15.54 x 2.62mm
46110220: 15.6 x 1.78mm
46110226: 17,1 x 2.62mm
46110245: 26.67 x 1.78mm
46110208: 31.6 x 2.4mm

Source has been scubagaskets.com

 

[Diving Gecko]

That's not a bad source! They do tend to round the numbers a bit on some of the dimensions. But still not bad.

BTW, if 46110208 is the one of the main seals of the reservoir, I am not sure it. will actually work. The Mares guns, I have have used a size that is more like 31.3 x 2.25mm (ID x CS) and I don't think it is a standard one. My Predathor main seals measure 27.3 x 2.36mm (ID x CS) so even though the cross section is comparable to the 2.4mm of the 46110208 the Predathor ring gets stretched quite a bit more being 4mm shorter.
My Seac main seals measured in at 31.14 x 2.18mm (ID x CS) and they are interchangeable with the Mares ones.

The only over the counter alternative I have found which actually works is one that I found in China at 31.6 x 2.2mm (ID x CS) or 36 x 2.2mm (OD x CS) in green color, so possibly FKM material.

 

[popgun pete]

A problem when measuring miniature "O" rings is that some are flattened even when brand new, probably by being produced in old dies that as they are resurfaced the mold halves get slightly closer together. Digital callipers can damage the rings if you put the jaws into the central hole, so the safest measurements are the OD and the ring thickness which should be the ring section width, but sometimes it is not and then you have to average the thickness measurements which is not ideal as rather than being squashed the sections may be oval in the first place.

 

[jimmy.k]

46110213 could be an AS568-004 o-ring measuring 1.78mm x 1.78mm (ID x Cross Section). Or 5.34mm x 1.78mm (OD x CS).
Other references in Mares literature: There is no direct '004' reference as in the example above but there is a reference to an 'O-ring 2007' which I think could possibly be to the Italian UNI standard of OR2007 which just so happens to be a 1.78x1.78mm ring).
Usage: Just looking at the numbers, and not knowing the diameter of the o-ring seat in your handle, this o-ring could make sense if your trigger pin was ø2mm, but I reckon yours might be ø3mm in which case it would be stretched quite a lot. That said, Mares were not always the most diligent in adhering to the best o-ring practices.

I measured the pin and is indeed 2mm thick so the 46110213 o-ring with 1,78 x1,78 makes perfect sense....using the 46110201 as the manual advises with 2,9 inner diameter doesn't look very wise. I prefer to install the original o-ring dimension Mares has produced the gun in the first place rather than replacing and experimenting with a different animal. By the way your research on O-rings has helped a lot.

Thanks again guys, you have solved many of my questions.

 

[popgun pete]

The body rings are useful as they are an unusual size. The price of 9 euros is about AUD 15 or 10 USD for 10 rings, plus shipping. They rely on them thinning as they stretch to go in the seating grooves of the body sections.

Top-Quality Diver Supplies & Accessories | Scuba Gaskets

Discover high-quality diver supplies and accessories at Scuba Gaskets. Equip yourself for unforgettable underwater adventures with our trusted gear. Shop now.

scubagaskets.com

The "O" ring pick tool is a handy gadget, although you can use a wooden toothpick. Plastic construction minimizes the risk of scratching the seats where the "O" rings sit.

Top-Quality Diver Supplies & Accessories | Scuba Gaskets

Discover high-quality diver supplies and accessories at Scuba Gaskets. Equip yourself for unforgettable underwater adventures with our trusted gear. Shop now.

scubagaskets.com

 

[jimmy.k]

I have been using this set for the last10 years, I bought it for my motorbike restoration and have been extremely satisfied with it. They work great in very tight places and found them very useful in hooking and stretching the o-rings slightly when passing them carefully over the grooves of the inner barrel without damaging them.
They are very affordable and worth purchasing them along with a set of pin punches, never use nails or other sharp object that can slip and damage your gun.

 

[popgun pete]

I worked my way through the Scubagaskets list and found which rings are which, as claimed by them.

OR R/1 46110201 trigger seal on Sten (31), Reef (46), Mirage (28); inlet ball valve seal on Sten 87 (46), Sten 2001 (46), Reef (46) https://scubagaskets.com/product/nbr-70-o-rings-soft-006/

OR 106 46110106 safety lever friction element Cyrano (60), Sten 2001 (60), pumping barrel rings Mirage (46) https://scubagaskets.com/product/nbr-70-o-rings-soft-610-ap7502/ or https://scubagaskets.com/product/scuba-o-rings-green-viton-sh75-610-ap7502/

OR 2031 46110107 piston ring 11 mm barrel Cyrano, Spark, Stealth https://scubagaskets.com/product/epdm-70-sh-011/
or https://scubagaskets.com/product/nbr-70-o-rings-soft-011/

OR 2062 46110220 barrel to pre-chamber bulkhead for 13 mm barrel Reef (71), Sten 87 (71), Sten 2001 (71) https://scubagaskets.com/product/nbr-70-o-rings-soft-016/

OR 122 BIS 46110206 barrel to nose cone seal 13 mm barrel Sten (9), Reef (22), Sten 87 (22), Sten 2001 (22) https://scubagaskets.com/product/green-fkm-115-viton-o-rings-oxygen/

OR 2037 (was OR 110) 46110110 piston ring 13 mm barrel Reef (18), Mirage (9), Sten 87 (18), Sten 2001 (18) https://scubagaskets.com/product/scuba-o-rings-epdm-70sh-012/ or https://scubagaskets.com/product/nbr-70-o-rings-soft-012/

OR 3062 46110228 barrel to nose cone and inner nose cone support Cyrano (22) https://scubagaskets.com/product/green-14-viton-o-rings-scuba-dive-pure-oxygen/ or https://scubagaskets.com/product/green-14-viton-o-rings-scuba-dive-pure-oxygen/

OR 2106 46110245 nose cone inner support to nose cone Cyrano (29) https://scubagaskets.com/product/nbr-70-o-rings-soft-023/

OR Special 46110208 main body or tank ring all guns Reef (20), Mirage (36), Sten 87 (20), Sten 2001 (20) https://scubagaskets.com/product/o-rings-mares-46110208-speargun/

Where there are two choices the rubber type changes, however pneumatic guns do not need oxygen class "O" rings which are usually green.

Note that the numbers in brackets are the part numbers on the exploded parts diagrams for each gun.
"Sten" is the first version of the gun until the rear grip shape and muzzle changed. "Sten 87" is the "Competition Line" model, "Sten 2001" is the current model with the "Cyrano" style rear handle. "Reef" is a continuation of the original "Sten" shape, but with modifications to reduce its production cost (some parts used less plastic, some parts were either simplified or omitted).

 

[popgun pete]

They also list these as Mares speargun rings, but the code numbers are not cited.

https://scubagaskets.com/product/nbr-70-o-rings-soft-119/ ID X CS : 23,47 X 2,62 mm

https://scubagaskets.com/product/nbr-70-o-rings-soft-123/ ID X CS : 29,76 X 2,62 mm

The Shore Hardness or durometer of the "O" rings is 70.

 

[jimmy.k]

They also have the following gaskets that you need to type the code on the search button to retrieve

46110242

003 O-Rings for Swivels NBR Sh70 - Scuba Gaskets

Scuba Gaskets - 003 O-Rings for Swivels NBR Sh70 ID X CS : 1,4 X 1,5 mm . View product.

scubagaskets.com

46110227

113 Scuba O-Rings NBR 70Sh - Scuba Gaskets

Scuba Gaskets - 113 Scuba O-Rings NBR 70Sh. camera, photography, underwater.

scubagaskets.com

46110102

007 Scuba O-Rings NBR Sh70 - Scuba Gaskets

Scuba Gaskets - 007 Scuba O-Rings NBR Sh70 ID X CS : 3,68 X 1,78 mm. View product.

scubagaskets.com

 

[popgun pete]

They also have the following gaskets that you need to type the code on the search button to retrieve

46110242 OR 2003 46110242 trigger seal on "Apnea" system Cyrano (49) Sten 2001 (49)

003 O-Rings for Swivels NBR Sh70 - Scuba Gaskets

Scuba Gaskets - 003 O-Rings for Swivels NBR Sh70 ID X CS : 1,4 X 1,5 mm . View product.

scubagaskets.com

46110227 OR 3056 46110227 barrel to pre-chamber bulkhead Cyrano (71)

113 Scuba O-Rings NBR 70Sh - Scuba Gaskets

Scuba Gaskets - 113 Scuba O-Rings NBR 70Sh. camera, photography, underwater.

scubagaskets.com

46110102 OR 2015 (was OR 102) 46110102 power regulator shaft seal and power regulator piston seal

007 Scuba O-Rings NBR Sh70 - Scuba Gaskets

Scuba Gaskets - 007 Scuba O-Rings NBR Sh70 ID X CS : 3,68 X 1,78 mm. View product.

scubagaskets.com

Added the part descriptions. That is most of the "O" rings accounted for except for a few used only on the "Mirage".

 

[Diving Gecko]

At some point, I will get around to finalizing that spreadsheet I have where I have the real sizes for most of these seals. As mentioned, I think scubagaskets (while still an awesome find - and the best source we have had so far) has taken some liberties on rounding some of the dimensions. Nothing too bad, at all but just makes it less clear what the standard equivalent is. The vast majority of these o-rings are from the AS568 series except for the main body seals and perhaps that weird R1 ring used in some inlet valves and triggers. I think it is Seac that also have a straight 2mm CS ring, so that brand uses a mix of newer metric series and the AS568 series.

 

[popgun pete]

Because Mares have used that body "O" ring in all their guns after the "Titan" it is probably especially made for them (in fact some Titans with the "Sten" muzzle use it as well). If you order thousands, maybe hundreds of thousands of a certain size, then a company will make them for you.

 

[popgun pete]

This is the "Competition Line" Sten 87 diagram. The fluoro green soft over-handle is part 40, Mares ditched it on the later versions of the gun as well as the two-piece fore-aft adjustable trigger (no great loss).

Click on it to see it at full size as this is a big file.