Autumn Bash 17th and 18th September 2022

[Neil54]

If a gas ram could be charged with air, I could do it myself.
Now a pressure vessel. I could use the cylinder off my pcp complete with quick fill.

Now what pressure in bar would create 40kg force?

[gtfreight]

You could try digikey.co.uk. They have a conversion chart on their site.

[TonyL]

Mmmmmm.....wouldn't have a clue.. Guessing volume and stroke will need to be taken into account? Would there be any known values on gas ram rifles with valves at the rear, like the Theobens and HW90, just to get a ballpark or would the different volumes and strokes involved render that information totally useless? And I think they vary from rifle to rifle, too?

[baldinio]

If a gas ram could be charged with air, I could do it myself.
Now a pressure vessel. I could use the cylinder off my pcp complete with quick fill.

Now what pressure in bar would create 40kg force?

aren't all the modern gas rams sealed units that you can't alter the pressure on mate? If you've got one like a theoben ram with a valve in it I would say use a stirrup or scissor pump as it's easy to over fill them, the theoben ones don't take much pressure at all. There's a vast difference between the he and none he rams too in terms of operating pressure. Forgive me if I'm teaching my granny to suck eggs here by the way. Probably should have asked at the start, what ram you pressurising?

[T 20]

aren't all the modern gas rams sealed units that you can't alter the pressure on mate? If you've got one like a theoben ram with a valve in it I would say use a stirrup or scissor pump as it's easy to over fill them, the theoben ones don't take much pressure at all. There's a vast difference between the he and none he rams too in terms of operating pressure. Forgive me if I'm teaching my granny to suck eggs here by the way. Probably should have asked at the start, what ram you pressurising?

I always took it that the rod was sealed by a lip seal, Chris.

So if you put the ram in a pressure chamber and increase the chamber pressure above the ram's internal pressure, then pressure will go past the lip seal and increase the internal pressure.

Obviously, if this is how they work then you can only increase ram pressure as there's no way of letting pressure out of the ram.



All the best Mick

[baldinio]

I always took it that the rod was sealed by a lip seal, Chris.

So if you put the ram in a pressure chamber and increase the chamber pressure above the ram's internal pressure, then pressure will go past the lip seal and increase the internal pressure.

Obviously, if this is how they work then you can only increase ram pressure as there's no way of letting pressure out of the ram.



All the best Mick

Ahhhh that makes sense now, I had totally misunderstood what was going on lol (I'm a bit thick innit )) I reckon it would be a mare to get the pressure just right without being able to let any back out again

[look no hands]

I always took it that the rod was sealed by a lip seal, Chris.

So if you put the ram in a pressure chamber and increase the chamber pressure above the ram's internal pressure, then pressure will go past the lip seal and increase the internal pressure.

Obviously, if this is how they work then you can only increase ram pressure as there's no way of letting pressure out of the ram.



All the best Mick

Well I had a Theoben AWT ram that leaked, so it must be able to.

[T 20]

Well I had a Theoben AWT ram that leaked, so it must be able to.

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[TonyL]

I haven't ever played with them so only going by what I've read, but do you also struggle to space them out at one end to add preload if required? Would seem really weird if you're not able to, even if by only a little to help. So many advantages over a conventional steel spring in theory, especially in terms of refinement if the set-up is correct, but, in practice, the metal spring offers up so many more ways of being able to fine-tune the system for individual needs and preferences. The "Rammer Bash" just wouldn't have the same ring to it either, would it?

[look no hands]

I haven't ever played with them so only going by what I've read, but do you also struggle to space them out at one end to add preload if required? Would seem really weird if you're not able to, even if by only a little to help. So many advantages over a conventional steel spring in theory, especially in terms of refinement if the set-up is correct, but, in practice, the metal spring offers up so many more ways of being able to fine-tune the system for individual needs and preferences. The "Rammer Bash" just wouldn't have the same ring to it either, would it?

Well I remember the old instructions from Theoben about fitting their drop in rams and it said that you couldn't add preload and you can't alter the length of the rod, like you say Tone, they do have their advantages and I've tried a few but like you know, the Diana ram I put in my Fenman was a bitch to cock but the aftermarket ram I have in my Independent is easy and is pleasant to shoot as well, I actually prefer springs if I'm honest, more flexibility and with a proper fitting set of delrin guides they are just as smooth.