Salvimar Predathor shaft, different tang/tail, incompatible?

[stefpix]

Hi

I have beeun using the Salvimar Predathor for several years, most with the vuoto / dry barrel modification.
In May 2025 I purchased 2 spare shafts in brown steel 17-4PH that is stroner, less flexible than regular stainless.
In August I tried one, and it would not load.

I noticed the tang/tail is a little different, with some scalloping. As hard I would push down, the piston would not move.

Too late to return them to dive inn. What is this tail for?
Is there a way to temove the tail/tang and replace it with one compatible with the Predathor? Is it screwed and glued?

The Salvimar website is not very clear, and now there are 3 different kinds of tails.

I was hoping to hear back from Popgun Pete, who is the ultimate authority on this forum, but apparently he has not been posing in a while.

I wrote also to Salvimar, but I still need to hear back.

Thank you!
Stefano

 

[sohayli]

No, it doesn't matter. I used Mares in the shaft I made myself. There won't be any problem.

 

[stefpix]

Hi, can you elaborate?

I heard back from Salvimar.

They changed the shock absorber with a hole of 8.5mm from 8mm and the tail of the shaft accordingly.
But i have nor heard back whether if the new shock absorbers are compatible with the old shaft tail.

How did you make the shaft?
I also wonder how would be possible to unscrew the tail without ruining the shaft, maybe with some vice pliers?

 

[vrokhlenko]

Hi

I have beeun using the Salvimar Predathor for several years, most with the vuoto / dry barrel modification.
In May 2025 I purchased 2 spare shafts in brown steel 17-4PH that is stroner, less flexible than regular stainless.
In August I tried one, and it would not load.

I noticed the tang/tail is a little different, with some scalloping. As hard I would push down, the piston would not move.

Too late to return them to dive inn. What is this tail for?
Is there a way to temove the tail/tang and replace it with one compatible with the Predathor? Is it screwed and glued?

The Salvimar website is not very clear, and now there are 3 different kinds of tails.

I was hoping to hear back from Popgun Pete, who is the ultimate authority on this forum, but apparently he has not been posing in a while.

I wrote also to Salvimar, but I still need to hear back.

Thank you!
Stefano

Between a garbage plastic slider (that should be replaced immediately with a stainless or titanium one) you have a metal ring. Is it moving freely on the shaft or it is stuck? The thing is - if the angle on the end piece is wrong (which I doubt) - you would still be able to load your gun because regardless of the shape of the end piece you'd still be able to push the piston down. However in this case the shaft would not be held by the piston and would slide out freely when you point the gun down. The fact that you can not move the piston tells me that something is stuck.
I just looked again at your photos and the end piece looks a bit thicker than usual. It should be around 8mm. You said you have a dry barrel attachment. Probably it would not let a thicker end piece through. Check with the calipers the diameter of your end pieces

 

[stefpix]

What salvimar told me is they changed the diameter of the shock absorber from 8mm to 8.5mm and the angle of the tail piece.

So the new tail piece is half mm wider and it does not go through the old narrower shock absorber hole.

I have not heard back again after I asked if the new shock absorber is compatible with the old tailpieces.
Also the new shock, absorber is sold as 8mm, when it’s 8.5mm. Which makes it confusing whether a replacement would be the old stock, or new model.

I never had a problem with the plastic line retainer.
It is disappointing that while they improved the shaft end piece,they are not transparent on the compatibility

 

[vrokhlenko]

What salvimar told me is they changed the diameter of the shock absorber from 8mm to 8.5mm and the angle of the tail piece.

So the new tail piece is half mm wider and it does not go through the old narrower shock absorber hole.

I have not heard back again after I asked if the new shock absorber is compatible with the old tailpieces.
Also the new shock, absorber is sold as 8mm, when it’s 8.5mm. Which makes it confusing whether a replacement would be the old stock, or new model.

I never had a problem with the plastic line retainer.
It is disappointing that while they improved the shaft end piece,they are not transparent on the compatibility

What do you call a shock absorber? The opening of your dry barrel attachment?

 

[stefpix]

What do you call a shock absorber? The opening of your dry barrel attachment?

In Italian is “boccola di ammortizzo” a plastic cylinder at the end of the barrel that the piston hits after you take a shot.

shock absorber bushing. This one is similar but not for the Predathor vuoto.

 

[vrokhlenko]

In Italian is “boccola di ammortizzo” a plastic cylinder at the end of the barrel that the piston hits after you take a shot.

shock absorber bushing. This one is similar but not for the ten Predathor vuoto.

I know exactly what it is - it broke in my Cyrano so I machined a new one out of acetal and reused a rubber sleeve. See, I noticed that 0.5 mm difference in diameter - I make my own end pieces. Looks like you just need to reuse the old ones - the thread should be the same. Or get some replacements - easy in Europe

 

[stefpix]

I know exactly what it is - it broke in my Cyrano so I machined a new one out of acetal and reused a rubber sleeve. See, I noticed that 0.5 mm difference in diameter - I make my own end pieces. Looks like you just need to reuse the old ones - the thread should be the same. Or get some replacements - easy in Europe

Yeah but I am in the USA. I wonder if there is a way to enlarge the hole in the old one. But I do not have any machinery. I could get a small file and make a larger hole. But ir would be uneven.
I could order the new shock absorbers. But would not want to buy something that does not work. And is the hole in the piston that holds the shaft different? My spearguns are fine. Salvimar customer service could be more responsive

 

[vrokhlenko]

Yeah but I am in the USA. I wonder if there is a way to enlarge the hole in the old one. But I do not have any machinery. I could get a small file and make a larger hole. But ir would be uneven.
I could order the new shock absorbers. But would not want to buy something that does not work. And is the hole in the piston that holds the shaft different? My spearguns are fine. Salvimar customer service could be more responsive

I can reduce your endpieces to 8 mm on a lathe. But they are interchangeable. I think you are overcomplicating things. Your thread is M6 x 1.0 on a 7 mm shaft. Just unscrew the old one and screw on a new shaft

 

[stefpix]

I can reduce your endpieces to 8 mm on a lathe. But they are interchangeable. I think you are overcomplicating things. Your thread is M6 x 1.0 on a 7 mm shaft. Just unscrew the old one and screw on a new shaft

Yes I thought of that. How can I unscrew the tailpiece without ruining the shaft? With pliers?

 

[vrokhlenko]

Yes I thought of that. How can I unscrew the tailpiece without ruining the shaft? With pliers?

Well, first of all you will not "ruin" the shaft - it is 17-4ph tempered to about 47 on a rockwell scale. You can scratch it. But to avoid that you need aluminum foil. The easiest way is to cut out a few strips from a soda or beer bottle. Now, the endpiece is threaded with a "thread locker" that is breakable. So ideally you need a vise and pliers. Wrap the endpiece in several layers of aluminum foil and the shaft where the pliers will grab it

 

[stefpix]

Well, first of all you will not "ruin" the shaft - it is 17-4ph tempered to about 47 on a rockwell scale. You can scratch it. But to avoid that you need aluminum foil. The easiest way is to cut out a few strips from a soda or beer bottle. Now, the endpiece is threaded with a "thread locker" that is breakable. So ideally you need a vise and pliers. Wrap the endpiece in several layers of aluminum foil and the shaft where the pliers will grab it

Thank you.

I usually use superglue on the threads of the speartip. If I need to unscrew it I put it on the flame of my gas stove and the heat loosens the bond. Would a flame do the same for the thread locker?
Anyway I would need to sort this out if I need to order spare parts from Europe in the future. The tariffs and new Trump regulations have made buying from Europe much more expensive and shipping to the USA pricier and more complicated.

 

[vrokhlenko]

Yes I thought of that. How can I unscrew the tailpiece without ruining the shaft? With pliers?

Also you must secure the end piece that you will screw one. One way is to use a thread locker but it will cost you a few bucks. Another way is to use Teflon tape that is used in plumbing. But any synthetic thread will do. Wrap it around the thread and screw on tightly. You do not want to lose it

 

[stefpix]

Also you must secure the end piece that you will screw one. One way is to use a thread locker but it will cost you a few bucks. Another way is to use Teflon tape that is used in plumbing. But any synthetic thread will do. Wrap it around the thread and screw on tightly. You do not want to lose it

Thank you. You are very helpful. Would superglue gel substitute for a thread locker?

 

[vrokhlenko]

Thank you.

I usually use superglue on the threads of the speartip. If I need to unscrew it I put it on the flame of my gas stove and the heat loosens the bond. Would a flame do the same for the thread locker?
Anyway I would need to sort this out if I need to order spare parts from Europe in the future. The tariffs and new Trump regulations have made buying from Europe much more expensive and shipping to the USA pricier and more complicated.

Heat might help you but you will break it just with a mechanical effort. As far as those tariffs - I hate them because I make a lot of my gear with materials I order from China and now it got very bad indeed. Those endpieces I machine myself and I also make slide rings out of stainless

 

[vrokhlenko]

I would suggest an oil-based paint or a nail polish. Nail polish is aceton-based. Superglue might become brittle. Last time I had to do it - I used a piece of a plastic bag!

 

[stefpix]

Heat might help you but you will break it just with a mechanical effort. As far as those tariffs - I hate them because I make a lot of my gear with materials I order from China and now it got very bad indeed. Those endpieces I machine myself and I also make slide rings out of stainless

Now I have to use DHL for purchases of small cheap items from Europe, as the europea. postal services and usps are not equipped to collect the duties.
When I ordered the shafts, fedex wanted to know the composition of the steel, and where the steel that Salvimar uses for the shafts is produced. It seems insane. .

On top of it in the USA spearfishing gear is marked up so much. Sometimes 2 or 3 times than the price in Italy or Spain for the same name brand mask. Anyway I am in New York, these days are terrible for spearfishing with storms and no visibility.

The new shaft tail ends by Salvimar look better and more durable.if I could solve by upgrading the shock absorber bushings which are $5/$6 each and figuring out if the pistons are compatible with the 2 different tail ends, I would be willing to upgrade those component.

But European customer services are generally not as quick or as good as US based ones to provide information.
Still, pneumatic spearguns are great and economical compared to the really pricy wooden band guns many use here.
I can mount a GoPro or other action camera at the end of the barrel with a silicone pipe mount. So simple.

The tariffs suck for most Americans and I doubt the next president will undo them or resurrect the de minimis exemption for shipments from abroad.

 

[vrokhlenko]

Now I have to use DHL for purchases of small cheap items from Europe, as the europea. postal services and usps are not equipped to collect the duties.
When I ordered the shafts, fedex wanted to know the composition of the steel, and where the steel that Salvimar uses for the shafts is produced. It seems insane. .

On top of it in the USA spearfishing gear is marked up so much. Sometimes 2 or 3 times than the price in Italy or Spain for the same name brand mask. Anyway I am in New York, these days are terrible for spearfishing with storms and no visibility.

The new shaft tail ends by Salvimar look better and more durable.if I could solve by upgrading the shock absorber bushings which are $5/$6 each and figuring out if the pistons are compatible with the 2 different tail ends, I would be willing to upgrade those component.

But European customer services are generally not as quick or as good as US based ones to provide information.
Still, pneumatic spearguns are great and economical compared to the really pricy wooden band guns many use here.
I can mount a GoPro or other action camera at the end of the barrel with a silicone pipe mount. So simple.

The tariffs suck for most Americans and I doubt the next president will undo them or resurrect the de minimis exemption for shipments from abroad.

You go around it by going to Europe and buying things there and bringing them to the USA. I have 5 shafts - all Salvimar plus one original from Mares. Plus I have 4 Mares Cyrano guns with interchangeable parts. The biggest issue are O-rings, but I bought enough from China to last me a lifetime. Plus some I even modified - for the trigger mechanism. It is very small.
The endpiece of the shaft does not have to be "better" - it can be made from a non-tempered steel like 304 or 316 that is very rust-resistant.
Spearfishing near NYC is absolutely atrocious - currents and lousy visibility. Plus you really can not target stripers. What's left - tautogs? I used to go to Rhode Island (Beavertail state park) and NJ (Barnegat light) but with new regulations it does not make sense. So I go to Europe (Azores, Canary Islands) every year for many years now