What is the cause of my freezing cold and dripping wet moderator after 75 shots?

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rodjava

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Sep 6, 2021
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San Francisco California, 94134 United States
www.allcalibers.com
Texan .257 LSS shooting AVS 85 grain slugs tethered at 3100 psi 1020 fps
Range at Petaluma CA. 65 degrees humanity 40% precipitation 1%

After aprox 75 shots, the moderator on my Texan 257 LSS gets "very cold to the touch" just below freezing and soaking wet.

I'm sure the freezing end of my barrel affect my POI.

I'm no "brainiack" and wonder what causes this wet and cold condition. And how I can prevent it?
Rod in San Francisco
 
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Adiabatic expansion of air coupled with an inefficient (or super high power) tune.

en.wikipedia.org

Adiabatic process - Wikipedia

en.wikipedia.org en.wikipedia.org

You can try to dial back the power, or get a longer barrel/run higher pressure so you don't have so much valve dwell.

Humanity is only about 34% of mammal biomass.

-Matt
 
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rodjava said:
Texan .257 LSS shooting AVS 85 grain slugs tethered at 3100 psi 1020 fps
Range at Petaluma CA. 65 degrees humanity 40% precipitation 1%

After aprox 75 shots, the moderator on my Texan 257 LSS gets "very cold to the touch" just below freezing and soaking wet.

I'm sure the freezing end of my barrel affect my POI.

I'm no "brainiack" and wonder what causes this wet and cold condition. And how I can prevent it?
Rod in San Francisco
Click to expand...
Look up the Joule-Thompson effect. The Cliff notes are; when you drop the pressure of a gas across an orafice it cools. If there is moisture in the gas it also cools and will coalesce. If the ambient temp is cool enough the condensation can and will freeze.
 
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Podna said:
Look up the Joule-Thompson effect. The Cliff notes are; when you drop the pressure of a gas across an orafice it cools. If there is moisture in the gas it also cools and will coalesce. If the ambient temp is cool enough the condensation can and will freeze.
Click to expand...

It's Joule–Thomson and that's a bit different than the adiabatic expansion of air going down a barrel, fwiw...

 
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Stubbers said:
Adiabatic expansion of air coupled with an inefficient (or super high power) tune.

en.wikipedia.org

Adiabatic process - Wikipedia

en.wikipedia.org en.wikipedia.org

You can try to dial back the power, or get a longer barrel/run higher pressure so you don't have so much valve dwell.

Humanity is only about 4% of mammal biomass.

-Matt
Click to expand...
Do you have a video in English? Sorry, I not sure what language that video is in.
 
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byjus.com

Joule Thomson Effect Definition - Joule Thomson Coefficient

Know what is Joule-Thomson effect along with Joule thomson coefficient based on thermodynamic principle, concept of inverse temperature and more by visiting BYJU'S
byjus.com byjus.com

Applications of Joule-Thomson Effect​


  • The cooling produced in the Joule-Thomson expansion has made it a very valuable tool in refrigeration.
  • The effect is applied in the Linde technique in the petrochemical industry, where the cooling effect is used to liquefy gases.
  • It is also used in many cryogenic applications. For example for the production of liquid nitrogen, oxygen, and argon.
  • The effect can also be used to liquefy even helium

byjus.com

Adiabatic Process - Definition, Equation, Reversible Adiabatic Process, Example, Differences, Video and FAQs

An adiabatic process is a thermodynamic process which involves the transfer of energy without transfer of heat or mass to the surrounding. Adiabatic process can be either reversible or irreversible.
byjus.com byjus.com

Adiabatic Process Example​


  • It is a process where there is a gas compression and heat is generated. One of the simplest examples would be the release of air from a pneumatic tire.
  • Adiabatic Efficiency is applied to devices such as nozzles, compressors, and turbines. One of the good applications of the adiabatic process.
  • The pendulum oscillating in a vertical plane is an example of it.
  • A quantum harmonic oscillator is also an example of an adiabatic system.
  • When we put the ice into the icebox, no heat goes out and no heat comes in.
 
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I would like to thank all of the members who chimed in so far.
Your contribution is appreciated. It really is.

However, I'm a simple minded man. (68) with only few years of community collage back in the 70s.

It's taken several months and more than a1000 rounds to perfect "the tune" for my Texan. Proof is my ability to split playing cards at 200 yards. So I'm not likely to change anything.

The Texan LSS has a shrouded barrel and I wonder if I insulated inside as well as outside of the shrouded barrel is it would cut down on the condensation?

The Texan is also a single shot loader. I typically shot a single shot every 12 seconds or so. And typically shoot 5 to 6 shots in a row, take break to analyze the shot groups and then rinse and repeat. Perhaps I'm shooting to fast and too often?

I use a oil/water separator with a molecular sieve on my air compressor. So I don't think very much water is in my tethered tanks.

So, I'm still looking for an simple explanation that a 6 year old would understand. lol

Rod in San Francisco
 
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rodjava said:
I would like to thank all of the members who chimed in so far.
Your contribution is appreciated. It really is.

However, I'm a simple minded man. (68) with only few years of community collage back in the 70s.

It's taken several months and more than a1000 rounds to perfect "the tune" for my Texan. Proof is my ability to split playing cards at 200 yards. So I'm not likely to change anything.

The Texan LSS has a shrouded barrel and I wonder if I insulated inside as well as outside of the shrouded barrel is it would cut down on the condensation?

The Texan is also a single shot loader. I typically shot a single shot every 12 seconds or so. And typically shoot 5 to 6 shots in a row, take break to analyze the shot groups and then rinse and repeat. Perhaps I'm shooting to fast and too often?

I use a oil/water separator with a molecular sieve on my air compressor. So I don't think very much water is in my tethered tanks.

So, I'm still looking for an simple explanation that a 6 year old would understand. lol

Rod in San Francisco
Click to expand...

Insulation would likely increase it.

Shoot more slow (either between shots or fps)

-Matt
 
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rodjava said:
I would like to thank all of the members who chimed in so far.
Your contribution is appreciated. It really is.

However, I'm a simple minded man. (68) with only few years of community collage back in the 70s.

It's taken several months and more than a1000 rounds to perfect "the tune" for my Texan. Proof is my ability to split playing cards at 200 yards. So I'm not likely to change anything.

The Texan LSS has a shrouded barrel and I wonder if I insulated inside as well as outside of the shrouded barrel is it would cut down on the condensation?

The Texan is also a single shot loader. I typically shot a single shot every 12 seconds or so. And typically shoot 5 to 6 shots in a row, take break to analyze the shot groups and then rinse and repeat. Perhaps I'm shooting to fast and too often?

I use a oil/water separator with a molecular sieve on my air compressor. So I don't think very much water is in my tethered tanks.

So, I'm still looking for an simple explanation that a 6 year old would understand. lol

Rod in San Francisco
Click to expand...
As a gas is compressed it increases friction, as the molecules rub together. Rub your hands together quickly and note the heat generated.

As a compressed gas decompresses it gives off the potential entropy stored and feels cool, like blowing your hands off.

Ignoring the closed loop aspect of entropy exchange consider this:

 
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