Feinwerkbau Air Cylinder Longevity

[Hsing-ee]

This subject has been discussed a lot on the internet.

There are two camps, those that say follow the 'dispose after ten years of use' as per the advice from FWB, and those that say this is a rule arbitrarily imposed by the ISSF with no basis in any actual risk of rupture.

Have there been any actual dangerous fatigue failures of the air cylinder in Feinwerkbau rifles and pistols?

One engineer suggested measuring the cylinders diameters and when they stop recovering their normal 'empty' diameter, then they ought to be scrapped.

I have bought an older FWB pistol and am slightly nervous as the two cylinders it came with are over 20 years old. I suppose I will just have to shell out £150 for a new one ...

[Jesim1]

I've never heard of any problems with any manufacturer, and a 20 year old FWB is probably better than the ones you buy today. There is no law for testing cylinders under 500cc, so most air gun cylinders are exempt, but if you get it serviced you could always ask them to check for wear, although I don't think I'd go to the trouble of replacing it unless I felt there was a need due to poor visible condition

[Hsing-ee]

I've never heard of any problems with any manufacturer, and a 20 year old FWB is probably better than the ones you buy today. There is no law for testing cylinders under 500cc, so most air gun cylinders are exempt, but if you get it serviced you could always ask them to check for wear, although I don't think I'd go to the trouble of replacing it unless I felt there was a need due to poor visible condition

Yes that is the conclusion I have come to as well, thanks for the confirmation. I did get a very high resolution micrometer screw gauge and measured the diameter of the spare cylinder, it is completely consistent all the way round and up and down, no distortions, so I think it will be fine.

[Shed tuner]

for steel I'd be checking the inside for rust. if none, it'll last forever.

for ali, I'm not sure whether any stress / fatigue would show up as small physical distortions ?

[Jesim1]

Microfractures, internal rust and stretching of the neck are what normally kill a cylinder in the larger capacities, I think with smaller ones it's far less of a problem, even internal rust can be shot blasted and still used, but probably cheaper just to replace if that's the case?

I think there is far more likelihood of an O ring going rather than a catastrophic failure.

[Hsing-ee]

Microfractures, internal rust and stretching of the neck are what normally kill a cylinder in the larger capacities, I think with smaller ones it's far less of a problem, even internal rust can be shot blasted and still used, but probably cheaper just to replace if that's the case?

I think there is far more likelihood of an O ring going rather than a catastrophic failure.

There seems to be some kind of burst panel in the cylinders, like a hole about 0.5 mm? So would it not just blat that out if it was feeling sick?

https://i.postimg.cc/BnfnDhxV/IMG-6490.jpg

[Jesim1]

There seems to be some kind of burst panel in the cylinders, like a hole about 0.5 mm? So would it not just blat that out if it was feeling sick?

https://i.postimg.cc/BnfnDhxV/IMG-6490.jpg

No idea bud It would make perfect sense, but I was not aware of it.

[Shed tuner]

burst disc will be for over-pressurisation. Won't help if the cylinder fails below that pressure...