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Salvimar Vuoto Bushing Damping sizes?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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New Member
May 31, 2021
Looking at spare parts online. I noticed 2 different sizes of bushing for the vuoto 8mm green and 7mm grey. Why is there 2 different sizes of bushing?

I have a vuoto 100 with factory 7mm shaft and I have a plus 100 with a 8mm shaft and 7.5mm? Does my vuto have a 7mm bushing or 8mm? Can I use my plus 100 shafts 7.5 or 8mm in the vuoto?
The bushing or shock absorber is sized to let the shaft tail stop through while simultaneously serving as a guide when first pushing the shaft tail into the muzzle. The tail stop diameter on 7 mm shafts is 8 mm and on 8 mm shafts it is 9 mm. A gun that is supplied with 8 mm shafts can shoot smaller shafts than 8 mm, but that is not always the case with 7 mm shaft guns. For example Mares original Cyrano which was strictly a 7 mm shaft gun would not accept an 8 mm shaft unless you put a drill through the shock absorber anvil to open it up (not recommended).
Salvimar vauum muzzles 20201 catalog.jpg


  • Salvimar vauum muzzles 20201 catalog.jpg
    Salvimar vauum muzzles 20201 catalog.jpg
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The Predathor Vuoto 100 comes with a 7 mm integral tip shaft, so it will have the 7 mm bushing in it. I actually have that gun and tried sticking an 8 mm shaft in it, but the tail would not go in very far. I unscrewed the nose cone tip and was going to pull the vacuum cuff out to get a better look, but it being greasy with oil and a smear of grease it was not going to come out. Rather than bugger it with pliers I gave up as the cuff is near new. When you need to remove the cuffs you can use pliers as the cuff is already stuffed. You can tell that a vacuum cuff is good as when you pull the tail out you hear a pop like pulling a cork out of a bottle. Wet your spear tails down before such an exercise and you will not stuff up the vacuum seals, I just put the spear tail under a running tap or you can stick it in a jug or glass of water.
Thanks. For testing. I did my own test. I found that my 7.5mm and 8mm shafts have a 9mm tail end and the 7mm shaft has 8mm tail end

I removed the vacuum cuff from the vuoto. I was able to load 7.5mm with a little more resistance than the 7mm. So would say I have the 8mm shock bushing in my vuoto. I am going to order a replacement 8mm bushing just in case I damaged it from testing. My goal is use the 7.5mm shaft in the vuoto as the 7mm does flex more than the 7.5mm
The bore of the bushing will be slightly bigger than the shaft tail stop, it will be a snug fit rather than a tight fit. The shaft tail should slide in easily before it jams the tapered spear tail end piece into the piston nose. Unless someone in the factory installed the 8 mm by mistake it should have the 7 mm bushing or shock absorber anvil. The next two gun sizes up have 8 mm shafts as you can see from the table below. When the shaft is travelling at high speed leaving the gun you don’t want the tail stop clipping the edge of the bushing as it will eventually damage it. One way to tell for sure is depressurize the gun and screw the muzzle off and check it directly. You will have to do that if you are swapping the bushing anyway. I much prefer 8 mm shafts, especially in longer guns, so was rather disappointed in the Vuoto 100 having a 7 mm shaft that is 117 mm long as measured from butt to tip. When ordered locally it was the only size they had in that model. Although on special at the time, I could have bought it for even less today, but would have incurred more shipping cost from an outlet like Scubastore for example. At one time they were asking 600 bucks for these guns in OZ!
Predathor Vuoto sizes.jpg
Here you can see a cutaway of the Salvimar Vuoto muzzle. This was before the shock absorber was changed in production to plastic. The assembly holds the shaft tail in centralized alignment to the muzzle and inner barrel axis and stops it tilting in combination with the shaft stop ring that sits in the muzzle nose. That ring or washer is not shown here, but sits in the recess cut into the muzzle nose, one for 8 mm and one for 7 mm located directly behind it.

From memory the bore through the 7 mm bushing has been measured at 8.5 mm and a photo was posted of it. I think the bore in the 8 mm bushing will be 9.5 mm, but have never measured it.
Salvimar vacuum muzzle.jpg

Found the diagram.
Salvimar Vuoto shock absorber.jpg
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Thanks for great feedback. Since they are brand new guns. I'll leave the 7mm shaft for now in the vuoto. When I get the 8mm bushing in. I'll remove the muzzle to check size and pump it back up.
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