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Mares snubnose at least 40 years old need help reviving it

gouthro

Well-Known Member
Feb 16, 2006
3
0
86
Found it in the basement and would like to put it to work. I am a little apprehensive however about squirting oil or wd 40 on it when I am not sure I should do that. I don’t know much about these but on reading the manual I see that you are supposed to pump it and then load the spear shaft down the muzzle. I tried that and the shaft didn’t seem to want to go. I didn’t want to try forcing it. I will try to load some pictures and hope someone can point me in the right direction. Thanks joe
 

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popgun pete

Well-Known Member
Jul 30, 2008
3,035
590
153
Australia
Your gun is the same as the Mares "Miniministen" and will be a single power gun. If the gun has no pressure after you have pumped it up then it must have a leak somewhere, either that or the pump is not working or leaking at where it attaches into the gun. That gun is relatively easy to disassemble and this thread will tell you how to do it. https://forums.deeperblue.com/threads/pneumatic-dismantling-how-to-get-inside.90024/
 

popgun pete

Well-Known Member
Jul 30, 2008
3,035
590
153
Australia
To undo the rear inlet valve body requires a simple tool such as this one. https://forums.deeperblue.com/threads/diy-tool-for-removing-rear-inlet-valve.93638/#post-870311

I would not use WD40 on it as the plastic pistons can be affected by it. You can spray the metal and black plastic parts as there are no problems doing that. When Mares restyled the "Sten" to a more angular shape in 1987 they renamed the previous "Sten" model as the "Reef", but it is still the same gun.
Mares Reef and Sten diagram pre 87 (800x659).jpg

Mares Sten diagram pre 87.jpg
 
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popgun pete

Well-Known Member
Jul 30, 2008
3,035
590
153
Australia
The side mounted line release dates from 1980 when Mares filed for a patent on it. Previously it was mounted on the trigger centerline as a downwards projecting hook.
Mares Sten side line release.jpg
 
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gouthro

Well-Known Member
Feb 16, 2006
3
0
86
Thanks very much for the detailed response, Pete. I will have to look at it closely. I was hoping not to have to take it apart, as I am not really mechanical. I can probably do it, though,and I suppose that after forty years of sitting, i may have to anyway. I know nothing about spearguns and thus don’t know whether it has air in it or not. And if it does have air, I don’t know how to let it out. My original problem was that the spear would not seem to load. The piston, I suppose, would not go down. Maybe corroded? Or, would that be because there is no air in it?

By the way, I was curious about the name, “Sten”, and wondered if it was named after the British stengun of World War Two? I have fired one of these and there certainly are similarities in appearance.

Thanks joe
 

popgun pete

Well-Known Member
Jul 30, 2008
3,035
590
153
Australia
To check the air pressure you depress the air inlet valve stem which is an inox ball at the rear of the gun with something like a wooden toothpick. Just a slight push and you will air hissing out as the ball moves. If no air comes out then the gun is out of pressure and needs to be pumped up. I bought a "Ministen" aka "Shortie" about a year ago of the same vintage and it held pressure, so the seals could still be OK in your gun.

I don't see it in your photos, but the spear should have a stop ring, shock absorber spring and a line slide on its rear end. The stop ring helps centralize the spear when you push it into the gun.

Download the Mares pneumatic gun manual from here which will tell you all the basic information. https://www.mares.com/shop/en-AU/downloads/manuals/other-manuals/manual-pneumatic-guns-multilanguage.html

As for the Sten name I don't know, but possibly its grease gun looks made people think of the Sten machine gun of WWII.
sten_mkIII_thumb.png

The above gun's name derives from the names of its designers and was named the "Sten", after Shepherd, Turpin, and Enfield. Otherwise Sten is Scandinavian for stone, being a boy's name, same as Peter.
 
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Diving Gecko

shooter & shooter
Jun 24, 2008
1,268
309
138
Shanghai
Hello @gouthro.
I wanted to say that you and your basement discovery are in the best of hands with Pete. Lots of examples in this corner of our forum of guns being resurrected or of people once uncomfortable taking pneumatics apart who now treat it like it's routine. I wouldn't be surprised if you can get your Mares back in the water with a little bit of guided effort.
These guns are, once you wrap your head around them, quite simple and we will all do our best to help you along.

I don't want be the bearer of bad news but I just wanted to give you a reality check. It's a very short gun and even though airguns are often more efficient than band guns and more powerful in smaller sizes, your "pistol" is quite short. Don't expect much range or knock down power from it. That said, I don't own a gun in that size but Pete does so he can give you a much better idea of what type of performance you can expect from it.

But back to fixing your gun - if the spear wont even go into the barrel more than just a few inches that would mean that the piston is indeed at the front. If it wont budge, it's either stuck mechanically or perhaps the gun is still pressurized - at high pressures you need quite a bit of force to move that piston. Pete's link will tell you how to get the air out.
If nothing major is broken or corroded, I think you can get the gun back to working order quite affordably. A set of replacement o-rings is USD 5-10, I think a new piston is less than USD 10 and perhaps you need a new spear.
Let us know if the inlet pump valve (the part at the back of the gun where you attach the pump) is a screw-in type with a female thread or a bayonet type and whether you have the pump or not? (When I say bayonet type, think of a modern camera lens mount where you insert a lens and just twist a quarter of a turn or so to marry the lens to the body). Reason being, the bayonet type is an older standard and whilst it should work just fine if you still have the pump, if you have lost the pump it is very hard to get a bayonet style pump so it would make a whole lot more sense to just get a new screw-in pump and upgrade the valve to the modern version. That part is less that USD 10, too though the pump might be double.
(I just reread your orginal post again and it seems like you do have the pump).
 

popgun pete

Well-Known Member
Jul 30, 2008
3,035
590
153
Australia
In order to check that the pump works OK just put your finger over the hole in the end of the pump with the handle already pulled back and then push the handle forwards. You will feel the pressure trying to push your finger away if the pump is working and it will blow the air out as you will not be able to hold back against it. Best to add some oil to the pump by putting some oil in a glass and use the pump’s suction stroke to pull oil into the pump, then squirt it out back into the glass. You can add oil to the gun by using this method, but I think it is best to unscrew the muzzle and pull the piston out and see what the oil inside is like in terms of being clean and uncontaminated. Milky looking oil has water in it and needs to be thrown out, but that is an unlikely situation unless the gun lost pressure in the ocean. I have had it happen twice, but that is over many decades of using the guns.
 
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popgun pete

Well-Known Member
Jul 30, 2008
3,035
590
153
Australia
Let us know how you get on. Those guns will shoot about 6 feet and I have bumped off plenty of bottom fish with mine, having owned two of them as I eventually wore the first "Miniministen" gun out. First was the original model and the replacement was a Sten 87 "Competition Line" model with the fluoro green over-handle cover (which was best left at home).
Miniministens 3.JPG
 
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gouthro

Well-Known Member
Feb 16, 2006
3
0
86
Thanks again for the comments. I have been a bit busy lately and haven’t had a chance to do much but I will be back to work on it soon. I did check a few of the things you mentioned. I tested the pump and it works fine. I released some air pressure from the back, as you mentioned. There is air in it. I tried briefly to load the shaft but still it didn’t seem to want to work and I didn’t want to force it, so I left it alone until I have more time to look at it closely.

One guy that I know suggests I should sell it and buy a pole spear. So it is encouraging, Pete, that you use yours. As I mentioned earlier I just do a little snorkeling these days and mostly only on holidays, so in a northern climate my time is limited. This just to say that A little gun may work for me. Will get back when I do a little more work on it. Joe
 

popgun pete

Well-Known Member
Jul 30, 2008
3,035
590
153
Australia
The shaft needs a good push to load it because the compressed air acts like a spring, so it may be that you have not pushed hard enough. I suggest that you bleed all the air out of it and then see if you can push the shaft in as then it will be very easy. You need a hand loader if you do not have one, you can see the black plastic hand loaders in my photo with the pieces of black elastic cord attached. Don't latch the gun so that you can return the piston to the muzzle end when you pull the spear back out. Then put 20 pump strokes into it and see if you can load it as that will be relatively easy. The “Miniministen”/”Snub Nose” pumping table is shown below.
Mares pump table R.jpg
 
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