Brass; changing dimensions

Longshooter - what is your theory about springback? Try to think in terms of individual atoms arranged in a crystalline lattice structure.
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Jetmugg,

Exactly, just the thing I am showing forth when I say molecular motion. Your interpretation is no different than mine. Just substitute "molecular" for crystalline lattice structure", and we are on the same page following this, as stresses, crowding, temp variations, etc. cause the physical dimensional changes of the brass case.

Perhaps you can differentiate between the two terms, but I think your point would be moot, because whether the atoms are contained in a molecule, or associated by latticework, the problem we are working with, physically work out the same, and end in the same conclusion.

So yes, you have a point about molecules, and crystalline structure, but it is only with the way the atoms associate with each other.

Brass is peculiar, some might say an alloy, and it's brass's physical characteristics that we are concerned with.

I think I did well with my explanation, considering I am not degreed on the subject.

I will say this, too often I see people jump into a thread, hammer someone, expand their own persona, then leave, having contributed relatively nothing to the thread. This crap needs to stop, or else we are not progressing on anything.

longshooter
 
I will say this, too often I see people jump into a thread, hammer someone, expand their own persona, then leave, having contributed relatively nothing to the thread. This crap needs to stop, or else we are not progressing on anything.
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longshooter said:
Jetmugg,

I think you don't know anything more about brass cartridge cases, than any of the rest of us do.

longshooter
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You mean like your quote above?

I just don't see any advantage to knowingly using the incorrect terminology (molecules), when the correct terminology is readily available. This is a forum based on the written word, and words have meaning. Why not use the correct words whenever possible?

Brass IS an alloy, it's not just that some might say it's an alloy, it IS by definition. "Brasses" are a family of alloys of copper and zinc. Individual alloys are specified by various naming and numbering designations.

It seems that you have a good fundamental understanding of stress and strain, but using incorrect terminology will not lead you or anyone else to a better understanding.

SteveM.
 
My answer is listed above.

The explanation I proposed to explain the "springback" phenomena is listed above, over the course of 2 posts. My explanation is based on my studies of the science of metallurgy, and uses the correct terms (dislocations, grain boundaries, lattice distortion, atomic diffusion). I mention that I'm metallurgical engineer so that folks will understand that I have formal education in this field, and that I'm not just making stuff up.

What is your area of expertise, Longshooter? I expect that within your field of expertise, there is specialized knowledge and language. I would expect that you would use the correct terms where appropriate.


SteveM.
 
Jettmugg,

My perceived explanation of cartridge case deviations is also listed above, in two posts. Our explanations do not substantially differ from one another. Perhaps you should have joined the discussion earlier, instead of joining later, for a sniping oppurtunity.

The thing that bothers me, is that these threads get killed, whenever someone steps in and snipes only. It's plenty fine to snipe, if it is deserved, just linger a little longer, and give a more thorough account, to set the record straight.

In other words, help the discussion, don't just be intent on disrupting it. Disruption is just plain counterproductive. And that is not the idea behind a forum.

Now, you have given some good info. I appreciate that. I'm sure others do also.

Back to the cartridge case, let's not lose sight of the person that started the thinking along these lines. Now, he might not have been correct in his terminology, but I don't see that as an oppurtunity for anyone to come on and hammer him, or try to make him look foolish.

You, as a professional person, should know this.

I am a stationary engineer, first class, as associated with central station electricity producing power plants.

Thank you for your time,
Michael Martell
 
Gilding metal is the softest type of brass commonly available. An alloy of 95% copper and 5% zinc, gilding metal is typically used for ammunition components.

Copper is an excellent heat transfer metal, My thoughts are that what you are seeing over time is the cause and effect of temperature changes in your storage area. Lets say you have a 10 degree rise in temp, this would cause the case to expand, maybe not much but expand it will, then you you have a negative 10 degree change the case will then shrink, but does it always shrink back to its original size that it was, it might be close.

Now you take into consideration that if this occurs numerous times over 60 days, is it possible that the expansion and contraction of the brass over that time has actually changed the dimensions permanently.

Longshooter this was taken from the dept of energy paper on compressed water .

Technically speaking, water can be compressed, but very little even at high pressures. For
practical design purposes, water is considered an incompressible fluid, that is, its density
does not change with pressure. The reason anything is compressible is due to how close the
atoms are packed together.

No pissing contest. Just food for thought


Good Shooting
DR
 
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