Larry
I don,t care what the manufactureer of the strain gauge say "it's calibrated to" That has zero effect on the numbers you are getting.
The strain gauge is measuring a strain from the surface it's mounted too. If that surface is not prepped correctly, Or to much or to little glue used Guess what there is a miss reading. The reading only needs to be off by a few thousandths of an ohm to be no good. See the thing you don't understand is these strain gauges are extremely sensitive. Calibrated from the factory means nothing when you are not attaching it to the steel in the same way the factory did. Then lets talk about yield point of the steel which can vary greatly depending on it's hardness. Do you have a rockwell tester in your garage? and can you tell me the difference in yield psi from say 35RC to say 40RC it varies quite a bit.
I did a tolerance stack on the gauge, mounting type and barrel steel and to put it lightly the tolerance is bigger then the pressure you are trying to measure.
This is why I don't like strain gauge readings as they are nothing more then a reference number. Not a PSI reading

Well Biscuit, now you've done it. Don't ever post any question on this forum dealing with pressures. You will get every cockroach smoked out of the woodwork with some of the coookiest ideas on what pressure really is. The bottom line is this; if, after you fire, the bolt is not sticky (harder to lift - and that is assuming you are using a bolt action) and the brass does not have any flow marks (ie. the face of the bolt impressioned into the case) and the brass extracts from the chamber easily (ie.falls out on it's own), then it is pretty safe to assume you don't have a pressure problem. And yes, if your primers fall out of the primer pockets while you are putting the cartridge in the rifle then you will probably want to back off the powder charge just a tad.
P.S. I use mostly post '64 Winchester CRF actions. I load to what almost everyone in this topic discussion would consider to be the higher end pressure side and, as you can see, I am still alive to tell about it. Also FYI every reloading/pressure issue I have ever had came from Remington/IMR products when they were owned by E.I. DuPont Co. back in the 70's- early 80's.
Also, KCStott is correct about the strain guage.

With CHE you have to have a reference also. Factory cartridges? I had some Remington .308 that blew primers on the first firing. So much for that "known quantity"!

Lets just get one thing clear here. I'm not saying that you should not use a strain gauge or to debunk anyones information. I'm saying why I don't use one and Why I think they are a joke when compared to precision measuring instruments.

There is to much hysteresis (inconsistency In it's ability to return to a known point of reference) in the system.
Not only are you required to use reference ammo as some would call it, but the wires to the gauge are not just any old wires either and the whole systems resistance needs to be calculated and compensated for. Saying the "computer" does it means it has a preprogrammed set of calculations that may or may not match the conditions you are actually shooting in. Sure it may have a temp input humidity what ever but it's not looking at how close you mounted the gauge to the case, How much glue did you use and how much will it flex before the steel does. Then there is the makeup of the steel itself. When you use the calculations to go from yield point to PSI a very small change in yield point will dramatically change the nominal PSI
Then what is the hardness of the steel. And is it the correct alloy that you are measuring for?
To many Ifs involved for me.

There is a reason why ballistics labs have hundreds of thousands of dollars worth of equipment Because it can not be replicated in a $500 box of parts.
It's like needing a set of calipers and using a tape measure Sure it will get you close and give you a number but we need to be a little more precise then that.
I looked into this subject with great detail. I found that every aspect of the system is critical to the number it spits out. and again were talking about a few hundredths to a few thousandths of an Ohm so even the solder joint you use to connect the wires will need to be taken into consideration. If we where talking Ohms instead of hundredth of an Ohm let alone thousandths of an Ohm I might consider building one. But since you need a reliable calibration source it's going to be difficult to do.
Oh and getting a reading from the sgs and comparing it to the reference ammo and then using a correction factor Is nothing more then a guess. How do you now what tolerances they lab barrel was built to? Is it middle of the road or is it minimum dimensions?
Which is why I'm considering building a universal receiver that will have an adapter to us a peizo system in direct contact with the shell case. Feed to an O scope. Just like the ballistic labs do.
But again my numbers will only mean one thing that they work in my gun and my gun alone. They will not give me a PSI reading that will directly correlate to the labs numbers. and they will not tell me if the rounds are safe to use in someone else's rifle


Just do what I did and start reading on how strain gauges are used and how they are used in a system. It will open your eyes. Granted I though I had found the answer to the pressure problem But nop it's not a system that I would trust. and until someone builds a better system I'll continue to look at my shell cases after the shot And stick to the manuals recommendations.

quote:

Originally posted by Stonecreek:

quote:

.After blowing ejector rod housings off 2 Ruger .45 Blackhawks,I learned max is NOT better.

Most people would learn that after one ejector rod housing

Scientific experiments depend on repeatability for validity!

quote:

Originally posted by tiggertate:

quote:

Originally posted by Stonecreek:

quote:

.After blowing ejector rod housings off 2 Ruger .45 Blackhawks,I learned max is NOT better.

Most people would learn that after one ejector rod housing

Scientific experiments depend on repeatability for validity!

Maybe thats why suicide bombers keep trying the guy running the test dies and therefore need to start all over again

kcstott

I would ask you then what methods are used to measure pressure of cartridges in firearms?

The strain gauges are correctly calibrated, correctly applied and the correct factor entered into the computor. Also the wires are of a specific type that address the issues you mention. Then too the "hardness" or leasticity of the particular steel is also known and entered in. Obviously you've not really studied much about the equipment I am using as it is hardly a "$500 box of parts". The use of reference ammuntion and the measured offset in pressure is industry standard practice. You, like Hot Core believe that ballistic labs measure pressures down to the umth degree and are absolute consistent. That is hardly the case. I have a lot of "reference ammuntion" that i test periodically in a specific rifle. The results are very consistent, at least they are within industry standards. Using the offset is not a "guess" it is a measurement.

To quote Dr. Oehler, it is an "equivelence" of measurement. So what is an "equivelence"? When you put 40 psi of pressure in your tires do we think it is really 40 psi exactly based on some psi locked in a vault some where? No we think it is based on some instrument that says what a psi is. When our speedometer says we are going 55 mph will the LEOs radar say we are going 55 mph and will not be stopped for speeding? When we measure the volts in batteries do we know that if it says it is 12.4 volts that it really is? Probably not. What we do know is if we put the same amount of psi with that gauge in our tires all will be well. If we go 55 mph according toour speedometer we are probably going to be ok within the "offset" the LEO is using before he'll stop you. If we measure 12.4 volts with a new battery and the old one measures 6 volts we can be pretty sure the old battery is about done. Thus if we measure a factory .308W and get a MAP of 52,700 psi and the factory says their MAP in their SAAMI pressure barrel was 53,400 psi for that same lot of ammuntion then we can assume that the psi we obtained is an "equivelence" of the psi the factory got. Then by testing our reloads similar to the factory load if we get over 52,700 psi we can correctly assume we are getting higher pressures than a similar factory load.

Obviously you have made a case for yourself against pressure measurements by instrumentation. That being the case you are probably flinching every time you pull a trigger on factory ammuntion. I do trust the information I'm getting from the Oehler M43. The information is very consistent with industry, SAAMI and CIP information. No the psi's I get may not be the exact same psi's as listed by the ammuntion makers. I do not expect them to be. Perhaps you also fail to realise that few of an ammuntion makers lots of ammunition actually are the MAP as most often listed in books and manuals. That figure is just the maximum allowabe average psi of any lot of ammunition for that cartridge. It is not what every lot of ammuntion of that cartridge is loaded to.

I am using different barrels than the factory SAAMI pressure barrels. Do you really think you get the same pressures as the factory test barrels in your rifles? If you do you are wrong. The different ammuntion manufacturers all use different barrels and thus there are differences in the psi measurement of even the reference ammunition. That is why the offset is used. It is not "guessing" but is using sound scientific technique for measuring presure.

When I get well within 3,000 psi in my commercial .308W barrel of what Winchester or federal gets in their pressure barrel with the same lot of ammuntion then that is a very close measurement. How do I know this? Well most of the manufactures also test their ammuntion in commercial barrels. I expect the pressure in my barrel to be lower because the internal chamber and barrel specs are not as tight as SAAMI specs for pressure barrels. The ammuntion makers also expect the psi to be lower in the commercial barrels.

When I get 4 differnt lots of 5.56 that give consistent psi and velocity readings with arsenal specifications and then 1 lot that gives a much higher pressure and velocity I trust and believe the results.

Do I think the M43 is going to give me the exact same psi as the factory pressure test? Of course not. However, it is going to give me a very good and reliable "equivelence" to make a much better decision on the psi in the cartridge I am loading for is generating than just "bolt lift".

I'd also bet that if a strain guage with the M43 were attached to the factory pressure barrel so the both would measure the pressure of the same shot from the same barrel that the psi readings of the M43 would be consistant with the psi readings of the factory pressure test machine. You don't want to take that bet because I sandbagged you, the test has already been done.

I also am not saying that everyone needs to get a M43. Far from it as it is an expensive proposition. However, I do believe my tests an others test have proven itself to be far more reliable than any other method available to reloaders to establishing the psi of there loads. The use of the M43 also has shown CHE, along with other pressure measuring devices, to be unreliable. That is what this and my previous posts are about, the unreliabilty of CHE.

Larry Gibson

quote:

Originally posted by Larry Gibson:
kcstott

I would ask you then what methods are used to measure pressure of cartridges in firearms?

Piezoelectric transducers in direct contact with the shell case

quote:

The strain gauges are correctly calibrated, correctly applied and the correct factor entered into the computor.

When I say calibrated I mean as a functioning system. Why is it that these strain systems (the Oehler system may be different) don't give you a tolerance to expect on the reading? Say +/- X PSI

quote:

Then too the "hardness" or leasticity of the particular steel is also known and entered in.

Ah I beg to differ. See when steel is heat treated it's yield strength changes along with it's modulus of elasticity. Not all steels are the same nor are all heat treated to the same hardness in the same process. 4140's yield point varies from 64 to 174 M psi And it's the yield point that you are measuring with the gauge. My ASME book of metals properties lists 49 separate yield points for 4140 depending on how it was heat treated.

quote:

You, like Hot Core believe that ballistic labs measure pressures down to the umth degree and are absolute consistent.

Not in the least. I believe they measure the pressure to an acceptable degree with in an expected tolerance range.

quote:

I have a lot of "reference ammuntion" that i test periodically in a specific rifle. The results are very consistent, at least they are within industry standards. Using the offset is not a "guess" it is a measurement.

Thats good that you do use reference ammo Most people that use these system fail to get the proper reference ammo to calibrate there system But using an of set is a guess because you have still not placed a known specific and as near exact psi load on your chamber. What I'm getting at here is you have no clue what the tolerances of the test barrel the lab used Most likely is is a tight dimension barrel but who knows for sure.

quote:

To quote Dr. Oehler, it is an "equivelence" of measurement. So what is an "equivelence"? When you put 40 psi of pressure in your tires do we think it is really 40 psi exactly based on some psi locked in a vault some where? No we think it is based on some instrument that says what a psi is. When our speedometer says we are going 55 mph will the LEOs radar say we are going 55 mph and will not be stopped for speeding? When we measure the volts in batteries do we know that if it says it is 12.4 volts that it really is? Probably not. What we do know is if we put the same amount of psi with that gauge in our tires all will be well. If we go 55 mph according toour speedometer we are probably going to be ok within the "offset" the LEO is using before he'll stop you. If we measure 12.4 volts with a new battery and the old one measures 6 volts we can be pretty sure the old battery is about done. Thus if we measure a factory .308W and get a MAP of 52,700 psi and the factory says their MAP in their SAAMI pressure barrel was 53,400 psi for that same lot of ammuntion then we can assume that the psi we obtained is an "equivelence" of the psi the factory got. Then by testing our reloads similar to the factory load if we get over 52,700 psi we can correctly assume we are getting higher pressures than a similar factory load.

true but I still am not convinced about the consistency of the system. See I had the equipment to build a home made SGS but when I stacked all the tolerances of the gauge, The O scope, and took into consideration all the variables it was just way to to precise to get a good measurement.

quote:

Obviously you have made a case for yourself against pressure measurements by instrumentation. That being the case you are probably flinching every time you pull a trigger on factory ammuntion. I do trust the information I'm getting from the Oehler M43. The information is very consistent with industry, SAAMI and CIP information. No the psi's I get may not be the exact same psi's as listed by the ammuntion makers. I do not expect them to be. Perhaps you also fail to realise that few of an ammuntion makers lots of ammunition actually are the MAP as most often listed in books and manuals. That figure is just the maximum allowabe average psi of any lot of ammunition for that cartridge. It is not what every lot of ammuntion of that cartridge is loaded to.

I am using different barrels than the factory SAAMI pressure barrels. Do you really think you get the same pressures as the factory test barrels in your rifles? If you do you are wrong. The different ammuntion manufacturers all use different barrels and thus there are differences in the psi measurement of even the reference ammunition. That is why the offset is used. It is not "guessing" but is using sound scientific technique for measuring presure.

When I get well within 3,000 psi in my commercial .308W barrel of what Winchester or federal gets in their pressure barrel with the same lot of ammuntion then that is a very close measurement. How do I know this? Well most of the manufactures also test their ammuntion in commercial barrels. I expect the pressure in my barrel to be lower because the internal chamber and barrel specs are not as tight as SAAMI specs for pressure barrels. The ammuntion makers also expect the psi to be lower in the commercial barrels.

When I get 4 differnt lots of 5.56 that give consistent psi and velocity readings with arsenal specifications and then 1 lot that gives a much higher pressure and velocity I trust and believe the results.

Do I think the M43 is going to give me the exact same psi as the factory pressure test? Of course not. However, it is going to give me a very good and reliable "equivelence" to make a much better decision on the psi in the cartridge I am loading for is generating than just "bolt lift".

I'd also bet that if a strain guage with the M43 were attached to the factory pressure barrel so the both would measure the pressure of the same shot from the same barrel that the psi readings of the M43 would be consistant with the psi readings of the factory pressure test machine. You don't want to take that bet because I sandbagged you, the test has already been done.

I also am not saying that everyone needs to get a M43. Far from it as it is an expensive proposition. However, I do believe my tests an others test have proven itself to be far more reliable than any other method available to reloaders to establishing the psi of there loads. The use of the M43 also has shown CHE, along with other pressure measuring devices, to be unreliable. That is what this and my previous posts are about, the unreliabilty of CHE.

Larry Gibson

For the most part I agree with the rest of your statement.
My issue is with the system I was going to build and the $500 boxes that are out there and not necessarily the M43, is how to calibrate the system as a whole.
How can I put an exact known psi load on the chamber and read a number, comp for it and then take notes. What bugs me the most about the system is lacking a true way to know the exact yield point of the steel and how much increase in psi equals movement of the steel. The dimensions and tolerances are too small to work with feasibly on a regular basis for me. When a barrel needs to be measured to the ten thousandth of an inch to run the proper calculation for a pressure vessel. You need to understand too that I was going to do all of this by hand No software involved so in adding everything up in the calculation if you were of by just a flicker on a measurement or not exact on the temp or humidity it would throw the result so far off it was useless.
Now the Oehler system may have a logarithm that compensates for as many of the variables as they can but the equation i am using relies upon accurate data to give you an accurate result.

Believe me I want to fully check my reloads and When I get this calibration issue under control I'll have a system put together. And Don't get me wrong when I say I look at my cases No where did I say I use PRE CHE or anything else.
I simply look at the case and look for typical signs of over pressure. Because I don't feel confident in PRE or CHE either.
Hell the brass alone can move more if you don't take a measurement at the same temp every time. We're talking ten thousandths of an inch here. set that case in the sun for a minute and see what happens.
Now Hotcore Don't go off on me. I'm not saying PRE and CHE is no good either. All I'm saying is without controlled conditions and a traceable standard no system is worth a darn.

KCstott

Obviously you have some knowledge regarding this issue. I could answer you statement for statement but I believe we basically agree. It appears you are simply missing some of the technical information. I would suggest you give Dr. Oehler a call. He is a very gracious gentleman of the old school and no doubt could fill in some of the questions/doubts you have with the correct technical information. I do not want to tread on some of Dr. Oehlers propriatory information of which I am privy and promissed not to divulge. However I'm sure Dr. oehler would discuss some of it with you.

Larry Gibson

quote:

Ah I beg to differ. See when steel is heat treated it's yield strength changes along with it's modulus of elasticity. Not all steels are the same nor are all heat treated to the same hardness in the same process. 4140's yield point varies from 64 to 174 M psi And it's the yield point that you are measuring with the gauge. My ASME book of metals properties lists 49 separate yield points for 4140 depending on how it was heat treated.

1.For the most part all steels have the same Young's Modulus.

2. The steel is not yielding when a shot is fired. It is being strained. Yielding is a permanent deformation. Yielding occurs when you exceed the elastic limit.

Go back and check your terminology.

quote:

Originally posted by Larry Gibson:
...you could at least contact the manufacturers and ask them what they do.

One of the jobs I had was Supplier Qualification Surveys. The companies I workd for were large enough to drive $$$multi-million$$$ contracts from various plants for the entire corporation. And as luck would have it, I have Surveyed Strain Gauge Mfgs.

quote:

You once again demonstrate your ignorence at understanding and inability to read. You insinuate that through the use of reference ammuntion the pressure machines are changed to read the correct pressure. This isn't so.

That folks is the "only way" to Calibrate a Haphazard SGS. As usual, larry has been blinded by his lack of education on the subject and hoodooed by marketing literature.

quote:

You really should go kill another thousand or so deer and then get back with us.

If I have the chance, I plan to do just that.

quote:

Each of tMarked as to specific lot and batch The gauges come from the manufacture calibrated as to;

Grid reference in ohms
TC of gauge factor %/100C
Gauge factor at 24 C
Transver sensitivity
Thermal output coeficients for a specific steel That information is provided for each gauge.

I agree it is, but..., it is not Calibration, it is Sorting by Resistance.

quote:

I recently discussed this with the factory tech rep. He was kind enough to send me all the technical data available on his companies products. He was quite humored when I discussed your insistance on a "alack of calibration" of their gauges. He mumbled something about the world being full of uneducated idiots refering to you. I couldn't help but to agree.

Actually larry, he was talking about "you". He knows, or should know, there is no Calibration for "individual" Strain Gauges - just Sorting. I agree he was probably laughing his clinton off thinking about you.

quote:

SAAMI does not have the "responsibility to distribute "reference ammunition. SAAMI is a voluntere organization and I'm sure many here would be surprised as to how many of the big name firearm and ammuntition companies do not belong.

You get dumber with each and every post.

quote:

Reference ammuntion is currently sold by Winchester and Federal with the stuff being sold by Winchester. All you have to do is contact their sales department and be ready to spend big bucks for the reference ammunition. All it takes is money. Once again Hot Core, you spout BS trying to impress those that don't know. Sorry, no cigar.

Actually more than Winchester makes the Calibration(Reference) Ammo. It is then sent to SAAMI for "Qualification Testing" and once it passes those Tests, then it is made available to the other Ballistics Test Labs.

quote:

The pressure of the factory ammuntition was known, Winchester and Federal supplied me with the test information of the specific lot I was using. Again your ignorance at comprehending what is so easily read is astounding. Do you need glasses? Amazing how you found the time for education while killing all those thousands of deer. Yet you question Dr. Oehler. That's pretty bold for a one eyed old fat man, eh?

And you are WRONG as usual. If they had supplied you with Real Pressure Data it would have been given to you as "XXkpsi, +/- Ykpsi". You never record the Variation when you post your totally worthless M43 trash, so it is obvious the manufacturers did not give it to your correctly and that you still don't have a clue about actual Pressure.

As far as Dr. Oehler goes, the guy does make mistakes. One huge mistake he made was selling the HSGSs to people outside a Ballistics Lab. As everyone knows, he no longer does this. For those who have followed these threads, it happened closely after this excellent discussion I had with him which showed the major problems of the M43 for the Home boys.

quote:

The two lowest psi lots showed no CHE and the highest psi of 65,300 also showed no CHE.

I actually believe larry was unable to get a CHE measurement. There is no doubt in my mind he is doing it incorrectly and never attempts to actually understand CHE nor PRE. Then he comes in making statements that it doesn't work. This is simply a situation of needing to know who is doing the posting and understanding his mental state. This is still the way it is.

quote:

However, most have seriously grown very tired of your outlandish claims and refuse to read them anymore. Perhaps that should be a clue to you and it would be a respite to me.

The "Truth" is often tough on fools. Anyone not wanting to read "the Truth" can either skip right on by my threads or use the Ignore Feature.

Your ignorance holds you back severly.

quote:

What bugs me the most about the system is lacking a true way to know the exact yield point of the steel

We don't need to know the yield point (elastic limit, actually - the lower elastic limit is where a small permanent dimensional change has occured while the upper elastic limit is when the material has broken). We only need to know the Young's Modulus of Elasticity. I'm not sure that changes much with heat treatment nor alloy types as SR4759 points out.

quote:

Originally posted by Rae59:
Well Biscuit, now you've done it. Don't ever post any question on this forum dealing with pressures. You will get every cockroach smoked out of the woodwork with some of the coookiest ideas on what pressure really is. The bottom line is this; if, after you fire, the bolt is not sticky (harder to lift - and that is assuming you are using a bolt action) and the brass does not have any flow marks (ie. the face of the bolt impressioned into the case) and the brass extracts from the chamber easily (ie.falls out on it's own), then it is pretty safe to assume you don't have a pressure problem. And yes, if your primers fall out of the primer pockets while you are putting the cartridge in the rifle then you will probably want to back off the powder charge just a tad.
P.S. I use mostly post '64 Winchester CRF actions. I load to what almost everyone in this topic discussion would consider to be the higher end pressure side and, as you can see, I am still alive to tell about it. Also FYI every reloading/pressure issue I have ever had came from Remington/IMR products when they were owned by E.I. DuPont Co. back in the 70's- early 80's.
Also, KCStott is correct about the strain guage.

Back to the basics!!!!!!!!!!!! Looks like the heavy artillary shelling is waning a bit.

Hot Core argues semantics regards to "sorting". How does he know? Just because he conducted a "survey"? Surely he jests. How about those gauge specifications are how they are made to certain specifications and criteris and the "calibration comes in the manufacturing to those standard specifications. As to the rest of his drivel....Hot Core shows his usual ignorance on the subject.

Larry Gibson

And so far at least I haven't seen anyone even MENTION perhaps one of the most important procedures in any electronic measurement system.

The RE-calibration, at some specified interval determined by the manufacturer, usually yearly at a minimum. Sometimes the re-cal can be done by the user but in other cases it must be done by someone who knows how, in an I&C lab.
Regards, Joe

that true JD
See what I am trying to get at with out all the hub bub is any measuring instrument need to be referenced to a known standard and the inherent problems make setting one of these systems up very troublesome
They will work and will produces accurate results but only if they are properly set up and every variable is accounted for.
The thing is Re-calibration is only for the electronics as the system need to be calibrated every time it's used and every time a new gauge is used.
You would never use a powder scale without checking it with test weights. then why use a SGS with out a good calibration

Just took a bit of time to go back and "Save" my discussion with Dr. Oehler to a Word Program. Now if the topic ever gets accidentally deleted, I will be able to replicate it exactly for everyone.

I find it interesting that he never did directly answer your question on the proper setup of an M43 With reference ammo and the like. And he has since stopped offering the system to the public. Makes you wonder if he figured out there might be to many uncontrollable or difficult to control variables????
I would personally love to see a system that could be referenced to a known standard using your own rifle.

The M43 was dropped due to parts not being made by his supplier anymore and suitable alturnatives not being available. This has been posted by Ken himself here in the past I believe.
He still offers his commercial strain equipment to the industry where it is accepted by SAAMI as suitable for their lab purposes along with Piezo.
Referance ammo isn`t what everyone thinks it is either. The ammo is simply made to SAAMI standard and sent to various labs where it is shot and the results sent back to SAAMI. SAAMI then compiles the data on the ammo and assigns it a pressure based on the result of the labs findings. There is no actual referance ammo that gives a exact known pressure as there is a referance measurement of say distance. Piezo and strain gages both only offer a "good estimate" of pressure built on a model. Both are notably more reliable in repetability and resolution then crushers and other past methods however.

quote:

Originally posted by kcstott:
I would personally love to see a system that could be referenced to a known standard using your own rifle.

Hey Kerry, Me too! Back when the M43 first became available, I believe I read about it in Shooting Times when one was sent to (the traitor) jamison. I was excited about it as Larry is about his.

Then a guy on the old "Shooters" Board got one named OKShooter(Stanley). I could not believe the luck that I could actually communicate with someone who had one. I even tried to run a CHE/PRE comparison Test with him. The results were always goofy and made no sense at all. I finally figured out he was "Neck Sizing" the Cases, so the PRE Results were garbage. No amount of discussion(on the phone) could convince him that he had to either FLR or P-FLR for the PRE measurements to be accurate.

Next thing I knew Stanley was posting 30-06 Loads he "claimed" were 100+kpsi(M43)!!! I called him out on it and mentioned Rookies were apt to try and duplicate some of that loonacy. I endured a buch of ignorant posts from fools that said the Rookies should know better. It had not dawned on me at the time that the HSGS was not Calibrated, so there was no telling how low the actual Pressure actually was.

Time passed, "Shooters" shut down and I was on another Board. One of those members was an Apprentice at a GunShop and bought a M43. However, unlike Stanley, I could communicate real well with this guy. We discussed the M43 on that Board and by phone. As we continued discussing it, the problems began showing up:
1. He had no way to Calibrate it.
2. He did not have access to a $$$HIGH$$$ CMM, so the Chamber measurements were "best guesses".
3. Normal Strain Gauge mounting issues(breaking, falling off, becoming loose, wires breaking away, etc.
4. And he needed a $$$HIGH$$$ Laptop to make the M43 run.
5. He had no clue as to what the Fudge Factor(Correction Factor) needed to be.
6. He had no idea how much actual "Variance" he should expect with a typical set-up.

He was an outstanding resource and convinced me about how useless any HSGS is outside a Ballistics Lab environment. Just as you can see in the above bickering with larry, when it comes time for larry to say what the "Variance" is in his kpsi readings, he is totally clueless about what I'm even asking. Dr. Oehler said it might be as high as 8%, I would speculate that is potentially a bit low when someone like larry or onefunz has one.
-----

What Ol'Joe posted is the latest info we have heard on "why" the M43 is not available to people like larry and onfunz anymore. I've gone on record as suggesting there is probably more to the story than has been told. If you look at the people who bought the M43s and Pressure Trace units, outside a Ballistics Lab, the percentage of them that actually understand their limitations is extremely small. I seriously doubt Dr. Oehler originally conceived that some of the folks buying his M43 would be so ignorant about how they actually work and the Pressure problems they potentially could create due to their lack of knowledge.

Now, that does not mean they could not "learn" if they wanted to. But as you can see in onefunz's old posts and larry's posts, they think that simply by buying the M43, they have somehow mysteriously gained all the Electrical, Mechanical, and Physics based info they need.

I respect Dr. Oehler more than ever for removing the M43 from the public market. He was a great guy to answer the vast majority of the questions I asked. And like you, I think there were a few answers he would rather have avoided.

HotCore

I agree and Very well stated.