I have been playing with PRE for a while now and have found it to be very helpful. From what I have read and been told, there seems to be a certain amount (lets say .0010"-.0015") of PRE that is acceptable whether it be a 22Hornet or a 300WSM. I would think that a .0015" PRE for a .330" wide case would be a MUCH greater pressure increase over factory ammo than the same .0015" PRE for a .555" wide case. With that being the case, shouldn't PRE be a percentage of the case width?

Deke

Hey Deke, There are a few problems with picking a specific amount for acceptable PRE, be it a range of increase or a percentage.

1. The final width at the Pressure Ring on the "Case" after resizing, varies slightly due to manufacturing tolerances in the Full Length Resizers.

2. The final width at the Pressure Ring inside the "Chamber" varies slightly due to manufacturing tolerances in the Reamers available to the firearms manufacturers.

3. The Case Annealing(flexibility) at the Pressure Ring varies from Lot to Lot and manufacturer to manufacturer.

3a. The strength of the Loads from shot to shot will affect the Work Hardening at different rates.

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Those reasons are why I recommend a person use a box of Factory Cartridges to establish a Benchmark Standard PRE. Then STOP when their reloads reach that same PRE. (Way simplified as you know.)

Working with Wildcats, as you like to do, it would be nice to be able to pick a range of increase or a percentage of increase, but it just doesn't work that way due to the inherent variations.

Measuring case heads and "pressure rings" has been proven to be an unreliable method to determine relative pressure or make determinations of maximum loads.

Jackfish, don't mean to blow you off, but I know better, both from the physics aspect and from experience. Is PRE perfect, NO. Is PRE better than a Strain Guage, I don't know. However, if you know what you are doing it is very useful, and without question less expensive than pressure testing equipment. This will allways be a continuing debate, but I suggest that debate occur on a different thread (which it already has on more than one occasion).

Hot Core, good to hear from you. The standard PRE for my 3030AI was derived from Rem150grCoreLokt ammo prior to converting to AI. It is important to note that my 3030AI did not have the pressure ring area of the chamber altered during the rechambering, therefore, the factory PRE is a good standard. It is important to note that I use the same manuf brass for factory PRE and reload PRE. I use only virgin brass w/factory chamberings, and use once-fireformed brass for determining max PRE of my reloads. I have also loaded the factory fireformed brass with identical loads of bulk fireformed brass of same manuf to determine that the particular lot of bulk fireformed brass I am using is practically identical to the factory loaded brass. Ken Waters explains in his book that factory ammo (for various reasons) is not loaded to the cartridge's potential and that the factory PRE can be exceeded by .0005"-.0015" (depending on the rifle). This is where my question pertains, pressure is a function of force divided by area. A 300WSM case/chamber has more area in relation to its width than a 22Hornet. Therefore, a 300WSM PRE should safely exceed that of a 22Hornet, leading to the idea of PRE not being a simple measurement, but some type of ratio based on case area and case width.

BTW, I do not own a 300WSM or a 22Hornet, I am just using them as a comparison for this discussion. My interest is to better understand PRE no matter what the correct answer is.

Deke.

PRE is strictly a relative system, incapable of giving an answer in useful units, such as PSI. It is also a very statistically noisy system. Two cartridges that experience pressures 15-20 KPSI apart can easily give you the same PRE.

You can reduce the noise by averaging, but the number of cartridges that must be averaged to supply a useful system is fairly large.

PRE can easily tell you to stop increasing load as low as 45 KPSI, and it can fail to warn you until you are over 70 KPSI.

If you like those odds, go for it.

quote:

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Originally posted by Deke:
I have been playing with PRE for a while now and have found it to be very helpful. From what I have read and been told, there seems to be a certain amount (lets say .0010"-.0015") of PRE that is acceptable whether it be a 22Hornet or a 300WSM. I would think that a .0015" PRE for a .330" wide case would be a MUCH greater pressure increase over factory ammo than the same .0015" PRE for a .555" wide case. With that being the case, shouldn't PRE be a percentage of the case width?

Deke

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You will find that thickness of the brass as well as its' hardness has an influence here as well.

denton,

If you wish to argue the merits of PRE please do it on another post since I am convinced that either you have not ever tried PRE or you do not know how to. I base this on the simple fact that my and others results are much different than yours that we have already wasted time on in other threads. You would save all of our time if you stuck with the question, which is whether PRE should be a set measurement for any cartridge or a percentage based on some function of case capacity and width.

El Deguello,
Good point. So should PRE be a function of case capacity/case width/AND wall thickness (I can see the variables adding up, maybe that is why Ken Waters kept it simple.....)?

Deke.

I am not an expert But,How many variables does it take before it is not accurate or repeatable??

Sean

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I am convinced that either you have not ever tried PRE or you do not know how to

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You are entirely mistaken.

475/480

The variables I alluded to were cartridge specific meaning 300WSM has certain brass thickness/case capacity/case width, etc. I know that two of these (capacity/width) are certainly different than a 22Hornet. Maybe variables was a poor choice of wording, maybe criteria is more accurate. The criteria are from cartridge to cartridge which would tend to make the PRE that more specific for a particular cartridge. My comment about simplicity was that Ken Waters did not write about going into this much detail, not that the additional criteria would invalidate PRE.

Deke.

Hey eldeguello, Nice catch and I totally agree that the case thickness has a bearing on it too. I seem to remember saying last year we agree on more than we disagree on, or something to that effect.

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Originally posted by Deke: Hot Core, good to hear from you.

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Hey Deke, Good to hear from you too. And I hope your Season was successful.

quote:

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The standard PRE for my 3030AI was derived from Rem150grCoreLokt ammo prior to converting to AI. It is important to note that my 3030AI did not have the pressure ring area of the chamber altered during the rechambering, therefore, the factory PRE is a good standard.

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I do remember you mentioning that previously. Sure helps get started.

quote:

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Ken Waters explains in his book that factory ammo (for various reasons) is not loaded to the cartridge's potential and that the factory PRE can be exceeded by .0005"-.0015" (depending on the rifle).

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You would be surprised at how some folks like to take Ken Waters words and twist them around 180deg to fit their agenda. Pitiful!

Anyway, as I sit here thinking about it, that could be (pure speculation on my part) due to the "Lower Pressure" exerted on cases during Fireforming. Kind of like shooting a slightly Reduced Load in the actual Wildcat. Plus, someof the Pressure will be used-up during the re-forming. So, allowing a bit more PRE than what is seen during the actual Fire-forming seems to follow a logical path.

quote:

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This is where my question pertains, pressure is a function of force divided by area. A 300WSM case/chamber has more area in relation to its width than a 22Hornet. Therefore, a 300WSM PRE should safely exceed that of a 22Hornet, leading to the idea of PRE not being a simple measurement, but some type of ratio based on case area and case width....

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I agree it would be nice if a person could come up with a method that allowed for all the variations, but I just don't think it is possible.

quote:

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My interest is to better understand PRE no matter what the correct answer is.

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A very worthwhile quest.

quote:

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You would be surprised at how some folks like to take Ken Waters words and twist them around 180deg to fit their agenda. Pitiful!

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Hot Core comes to mind.

Hotcore,

My seasons went well. The highlight was with my 7yr old daughter on her first big game hunt for Antelope. She did great on a 400yrd stalk with plenty of crawling and belly crawling (I being the triggerman was actually the one getting worked up, she was cool, she listened to dad and did everything right). Did you get to hunt and/or are you still hunting? I will be going after another Elk next week on a depradation hunt (killed a nice fat cow back in October, but the freezer is being emptied fast, 7yr old daughter will be going on this one too).

Hotcore QUOTE: Anyway, as I sit here thinking about it, that could be (pure speculation on my part) due to the "Lower Pressure" exerted on cases during Fireforming. Kind of like shooting a slightly Reduced Load in the actual Wildcat. Plus, someof the Pressure will be used-up during the re-forming. So, allowing a bit more PRE than what is seen during the actual Fire-forming seems to follow a logical path.

Not sure what you mean by the above quote. Are you saying that the one time fireforming alters the PRE measurements significantly when I work up loads later with the once-fired brass vs the PRE I established with the factory ammo in my factory chambered 3030?

Thinking more about case thickness, the "expected" case thickness could be factored in if there are known and/or specd thicknesses for a particular cartridge. If there is not a thickness that can be relied upon (vary too much from case to case of same cartridge, etc.), then thickness should not be factored in....

As far as someone "coming up with a method that allowed for all the variations," that I do not want to go through the brain damage for. I really only want to look at the sifnificant criteria. I am wondering if case capacity factored with case widths from cartridge to cartridge is one of the criteria that would warrant different PRE's (for example, .0010" max for 22Hornet, .0015" max for 300WSM, if both were for the same rifle/action, etc.).

Deke.

I've been reloading high intensity rifle cartridges for exactly 40 years now, and have never found attempts to measure the "pressure ring" (whatever that may be; the concept seems to vary from shooter to shooter and cartridge to cartridge), to be useful.

The first problem is that the brass may be out-of-round by more than the expected expansion, so you would have to measure the EXACT place on a given cartridge head to have dependable data.

The second problem is that most cartridges don't present a very useful place to measure. For example, it is difficult to measure the case body just in front of the extraction groove on a rimless case, and most PRE advocates don't like measuring the rim, but a measurement in front of the solid base of the brass is absolutely meaningless. Belted cases obviously have some bit more metal to resist expansion than non-belted cases, so how does one correlate, much less reconcile, the two?

And thirdly, the degree of expansion is so small that it is extremely difficult to measure with an ordinary micrometer. The expectations of the person doing the measuring may skew the "measurement" by more than the amount of variation one is looking for.

In a modern bolt action rifle, if pressures are "dangerous", then case head expansion will immediately manifest itself in loosened primer pockets on the first shot using new brass. If pressures are "undesirably" high, then primer pockets will loosen in just a few shots with the same load. When primer pockets last for five or more shots with the same load, then what else do you want? The primer pocket is "nature's" own case head expansion measurement, so pay attention to it.

By the way, if the action is other than a modern bolt action (or its strength equivalent), the you will reach dangerous pressure long before you have readable pressure ring expansion, so what's the use of PRE to begin with?

Disclaimer: I may not be as smart or as talented as other reloaders. If you, like the very respected Ken Waters, have the skill and the talent to use PRE, then by all means, use it. I may regard it as superstition, but we are all free to pray to god(s) of our choice.

Stonecreek,

I appreciate your experience as well as others and have found PRE vs other pressure "checks" a very devisive issue that I don't want to clutter this post with, but acknowledge that I don't own it and you/others are free to post whatever you like about it. Bottom line is that my methods of using PRE works for the cartridges I am currently working with. I constantly cross-reference other methods/signs/data, etc and I have found it very useful. I hope that everyone whether using PRE or whatever don't depend on only one check either.

I am confident as others are that I "have the skill and the talent to use PRE." I wish others the best success in whatever load development methods they use.

Deke.

Hey Deke, First off, That sure is great about being able to take your daughter along on the Antelope hunt. Sure glad for the both of you. And now going on an Elk hunt together. Get lots of flicks of her with you on the hunt. They grow at an "Exponential Rate" now.

Did not get to hunt this year(due to the family members health), but had all kinds of great offers from very old friends to come hunt their farms. Even had one of them tell me to come over to his place and shoot this Spring. I do hope to be able to pull that off. Maybe some hunting this year if things "heal up" so to speak.

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Are you saying that the one time fireforming alters the PRE measurements significantly when I work up loads later with the once-fired brass vs the PRE I established with the factory ammo in my factory chambered 3030?

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This gets into one of those areas where speaking in "absolutes" can be right, wrong or inbetween. Yes, some amount of Energy (Pressure in this situation) is "used up" during the Fire Forming. But due to all the variables, it isn't possible to say exactly how much. It would be nice if we could, but it just isn't reality.

That is another reason why you have to watch all the Pressure Indicators.

I was flipping through PO Ackley's Volume II today and was thinking about your original question. It is perhaps easiest to understand that with a relatively blown-out case-wall(pre-improved by the factory) cartridge like a 270Win, 308Win, 300RUM, etc., you just can't use the 0.0005"-0.00015" PRE "Over the factory Load" because they are already loaded to about the SAFEST MAX you can get.

Then when you take a cartridge like a 257Rob in a modern bolt action and turn it into a 257Rob AI, you not only get the benefit of straightening the case walls, but you can typically SAFELY increase the Pressure to that of more modern cartridge designs. Both of them allowing for more "measured" PRE while remaining SAFE.

In your 30-30 AI, I'm not sure what to look for as "additional" PRE. This is one situation where the amount of Velocity Increase as measured by a chronograph can be very beneficial to you. And, I know you are already doing that.

Increasing the Velocity to say 150fps over the original 30-30s Velocity as measured "prior to" being reamed out to the AI might be the best way to approach this. And using a Powder considered on the "Slow" side for the 30-30 which will extend the Pressure Curve over more time.

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Here is where it would be nice to try and convince you to just get a 308Win in a M7 or Wby U-Lt, but I also know that is not what you are looking for.

quote:

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However, it isn't simple. Also, measurement error of the magnitude of 0.0001" in typical firearm design amount to a pressure estimation error of ~ 5000 psi.

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I went to the trouble of setting up a Mitotoyu .00005" blade micrometer, on a granite inspection plate, and doing a repeatability study on my ability to get the same dimension off the same brass.

When brass is formed to the inside of the chamber, it is not perfecly round. As you rotate the brass, to find the PRE "high spot", per the Ken Waters instructions, you do not always find the same high spot. The Effective Resolution of the system for me turned out to be .00017", nearly two tenths.

With .0001" representing 5,000 PSI, the problems with such a system are readily apparent. Some may recall that I have previously posted the standard deviation of the random error in the system as 6,800 PSI--quite consistent with what I've just said here.

Lest you should think that it was somehow sloppy technique, I did the same thing at the case head, measuring at exactly the same spot. My Effective Resolution using this method was .00005", the specified limit for the micrometer alone.

The PRE system is too full of random noise to be a good practical system. It does give you an answer every time, but the the answer is highly influence by random events. Since "pressure signs" don't begin until over 70 KPSI, you have no practical way of detecting the fact that you're over pressure, when that happens. CHE is even less reliable.

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Originally posted by Hot Core:
Hey eldeguello, Nice catch and I totally agree that the case thickness has a bearing on it too. I seem to remember saying last year we agree on more than we disagree on, or something to that effect.

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Originally posted by Deke: Hot Core, good to hear from you.

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Hey Deke, Good to hear from you too. And I hope your Season was successful.

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The standard PRE for my 3030AI was derived from Rem150grCoreLokt ammo prior to converting to AI. It is important to note that my 3030AI did not have the pressure ring area of the chamber altered during the rechambering, therefore, the factory PRE is a good standard.

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I do remember you mentioning that previously. Sure helps get started.

quote:

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Ken Waters explains in his book that factory ammo (for various reasons) is not loaded to the cartridge's potential and that the factory PRE can be exceeded by .0005"-.0015" (depending on the rifle).

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You would be surprised at how some folks like to take Ken Waters words and twist them around 180deg to fit their agenda. Pitiful!

Anyway, as I sit here thinking about it, that could be (pure speculation on my part) due to the "Lower Pressure" exerted on cases during Fireforming. Kind of like shooting a slightly Reduced Load in the actual Wildcat. Plus, someof the Pressure will be used-up during the re-forming. So, allowing a bit more PRE than what is seen during the actual Fire-forming seems to follow a logical path.

quote:

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This is where my question pertains, pressure is a function of force divided by area. _A 300WSM case/chamber has more area in relation to its width than a 22Hornet. Therefore, a 300WSM PRE should safely exceed that of a 22Hornet, leading to the idea of PRE not being a simple measurement, but some type of ratio based on case area and case width._...

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I agree it would be nice if a person could come up with a method that allowed for all the variations, but I just don't think it is possible.

quote:

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My interest is to better understand PRE no matter what the correct answer is.

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A very worthwhile quest.

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Yes, fellers, I seem to recall that we discused this subject not too long ago, and shed more heat thatn light at that time also. I'm afraid it's gonna turn out the same this time.....

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Originally posted by ScottS:
I also agree that with the rimless cases the PRE method does not provide sufficient cushion between pressure read and potential case failure.

However with a RIMMED case, which is immensely stronger than a rimmed case (for example the case head a 30-30 roughly is as strong as a 416 Rigby!!) PRE can provide adequate warning that you are in a realm you best not be in!!
Scott

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Wait a minute....

you just said it wasn't effective in rimless case...


then said it was effective in a RIMMED case...

as the rimmed case was as strong as a rimless case head?

HUH?

In fact, if one accepts PRE as good OR bad, one must accept it for the SAME reasons in all rounds...

FOr instance..

if you can't tell if it's 50,000 or 65,000 in a case, that's ALWAYS bad....


and, if the case shouldn't even BE at 50,000, not knowing if you are at 65 could become, well, steel rain.

Funny that you infer the operator wouldn't be able to hold "that level of measurement" rather than the actual issue, that the case doesn't REPEAT to that level of measurement...


jeffe

ScottS

You've obviously put some real thought into this, and have some sound reasoning behind your statements.

I would agree that your line of reasoning puts some reason to the mean CHE that will be observed.

The problem I have with that is that it does not predict the standard deviation of the CHE's that will be observed... scatter around the mean.

I have tested CHE in a rimmed cartridge, and the standard deviation of the CHE corresponds with 7,500 PSI. So, there is so dang much random noise mixed in the system that you have to average a large number of cartridges to get acceptable repeatability.

An average of 9 cartridges will cut random noise by 3. 7,500/3 = 2,500. Two SD's give 95% confidence. So, if you average the PRE of 9 cartridges, you are 95% sure that your cartridges are in a 10,000 PSI tolerance band around whatever you're comparing with.

You can get it down to half the error by doing twice the cartridges, so 36 cartridges cuts your error down to plus or minus 2,500, and 72 cartridges gets it down to 1,250.

You have the same problem with whatever you're trying to compare with. In order to get a clear picture of your standard of comparison, you have to do an unrealistic number of averages, because of the variation.

I've never said the systems wouldn't work. They manifestly will. It's just that there is so much random error, that you have to do an impractical amount of averaging to get repeatability that is worth a hoot.

ScottS

I think your arguments are well reasoned. I'm a little skeptical of the premise that rimmed cases are stronger than rimless. Ackley ran an experiment that disputed that, but the results may not be totally conclusive.

Your fundamental starting point, that the chamber is a really strong spring, that gets temporarily stretched when the gun goes off is, in my opinion, exactly right. That's probably one of the clearest ways I've heard it expressed. And I think the mechanical strain gage analogy is a good one.

My experiment says that the 5,000 PSI estimate is optimistic, by a fair bit.

Other than that, I think we are in violent agreement.

Since this is potentially a safety issue I will put my foot into it again.

Everyone reading this post should be advised that ScottS is a notorious miscreant who has posted on this site for years under a bewildering array of handles (ToddE, Axel, etc.) and in many cases assuming a posture of technical expertise, posting material that has the ring of technical rigor, but which is entirely a hodge-podge of borrowed terminology and mischievous imagination.

Please do not take any of his counsel on pressure (or any other technical question) seriously.

In the past there were watchdogs that kept guard over this site, but I suppose that they have wearied of their thankless task. In general it is wisest to simply ignore his postings, as any rebuke invariably results in an interminable merry-go-round of rhetorical gamesmanship (sometimes involving new identities that alternately rebuke and defend the exposed offender). In a question of safety, however, I feel moved to act.

I am a practicing mechanical engineer in the field of ordnance and to address a few thoughts posed in this thread, I agree with several that one must be aware that many variables (read that as "uncertainties") enter into any strain measurement approach of estimating chamber pressure. It does work and was used for many years by the industry using special instruments and small copper cylinders. However, those copper cylinders were tested lot by lot for their mechanical response to known stresses and that response was used with a standard data set for the purpose of correcting the tested measurement. The handloader does not have this facility. You would need test data from the manufacturer on the case material and the test pressures (and just to make it more fun, if you shoot your loads in 40 deg F weather, that will change the effect on the brass too).

Brass work hardens. That means that its elasticity is reduced and its strength increased with mechanical strain (ie, deformation). So, indeed, when you fireform a load in virgin brass, that produces a different residual material state than if you take cases that were once fired factory loads. And unfortunately you really know nothing about the strength or elasticity in either case. While comparing to factory strain seems reasonable, it is no more likely to be correct than comparing to twice-fired cases or some other unknown load. Work hardened brass will allow higher pressures before plastic (permanent) strain is seen, and the evident strain will be small (because elasticity also diminishes). So, some specific measure of strain says nothing in absolute terms about the pressure (which is why ScottS's remark about 0.0019 strain indicating definite yield in the barrel is incorrect). Anytime you get plastic strain in the barrel you have wildly exceeded the safe margins for a load and you will see evidence of that which will be plain to the naked unaided eye (if you still have one).

The case is a gasket. It yields at stresses close to the maximum operating pressure of modern firearms. It should fail long before the steel in the barrel approaches failure. That is (strangely enough) a safety. Blowing a case is not nearly as nasty as blowing a barrel. Don't misunderstand that using hard brass makes the loading process safer. It means that you will have little or no warning when you have exceeded the safety margin or prior to a serious failure.

A certain degree of strain in a case is simply evidence of stress that exceeds the yield point for the brass at that initial state. Afterward it has a higher strength and will exhibit less strain the next time it is loaded to the same pressure (until you get a bit beyond the yield point at which it starts to run away). You cannot afford to use loads that allow case yielding to progress.

Since stress is a function of case geometry, you get different results at different places. The strain does not scale with case diameter, though, in the sense that someone was suggesting. There is an allowable margin of plastic strain in soft brass that will be similar for a given pressure in any size of case of interest to us. Big cases do not have either more or less allowable strain than small cases, assuming they are made of the same material in the same state and with similar thickness. The dimensions of the chamber do not affect the pressure or the stress state of the case.

There is a popular myth to the effect that the diameter of the case head or the body taper is in some way related to the force acting on the bolt using the F = P*A relationship, but this would only be true if the case were a fluid (and still untrue as far as body taper regardless). The chamber pressure acts equally in all directions on all internal surfaces of the case because it is fluid pressure, but the stress state of the case is that of a solid material with mechanical properties.

Pressure estimation without the benefit of true pressure measurement instruments is speculative at best. I try to keep the measured strain very small and to use cases in the same condition and take multiple measurements from different locations on the circumference. Pushing the envelope in terms of performance is always risky. My advice in that regard is to just move up to an appreciably bigger cartridge and load it modestly.

quote:

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The modulus of elasticity DOES NOT change with work hardening!

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Oooops.

My, My, this has gotten quite heated. For those who did not catch it, I do not use brass for PRE load development more than once after fireformed in a wildcat. For factory cartridges, I use virgin brass. Therefore, brass has not been workhardened significantly. All bulk brass has been compared to PRE's of other brass w/identical loads for comparison of elasticity, and any measured differences are noted/considered. Boy this is a hot topic.

I finally decided to consult my live in mechanical engineer (wife) and she set me straight. In the 2-dimensional (cross section of case), a 50% increase in width equals a 50% increase in circumferance (which is the area the force is exerted and pressure exerted. Therefore, given the same rifle, a 22Hornet and a 300WSM will have the same PRE.

I guess I will now monitor the post for the merits of PRE.

Deke.

I apologize to everyone for attempting to share my meager knowledge.

I shall not make this mistake again.

Oh, don't go away mad... or even go away for that matter. This is called learning. I've learned quite a bit from people on this forum. When I am wrong, I have the great pleasure of replacing an erroneous old idea with a better new one.

quote:

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Originally posted by ScottS:
I apologize to everyone for attempting to share my meager knowledge. ... I shall not make this mistake again.

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Hey ScottS, I just went back to try and locate your original post to see what all the heated focus on it was based on. Now I see you have deleted it.

Darn shame that you allowed anyone to run you off.

I personally don't like a lot of posts I see on these threads, but we all just don't think alike. Nothing wrong with that.

It should be left to each reader as who to believe. If they happen to believe someone who is wrong, it is self correcting as the believer gains experience. A lot of people will then be getting a bunch of good laughs at that persons expense.

So, if you are faking people out (like some others on this Board), then it is best to turn tail and run. If on the other hand you believe you are correct, are open to discussion, and can change your mind when you are proven wrong, it would be to your benefit to continue posting.

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From Deke: Boy this is a hot topic. ... I guess I will now monitor the post for the merits of PRE.

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Yes indeed, threads of this type bring out all kinds.

Since you already know how well PRE/CHE works, it is easy to learn that when you see someone who has no concept of the merits of the very best Pressure Detection Methods of all time and choose in their ignorance to berate them, it is best to just ignore that fool's desire to do nothing but argue.

Of course, if you are having a tough day for whatever the reason, you can always go back to read them and get a few good chuckles.

quote:

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Posted by Hot Core

If on the other hand you believe you are correct, are open to discussion, and can change your mind when you are proven wrong, it would be to your benefit to continue posting.

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Good advice, Hot Core. However, of all the people on the board, you seem most resistant to evidence.

1. Standard list of Hot Core fabrications, unsupported by any known facts or credible references, all posted on this board by Hot Core, for everyone to see---
1.1. Mounting a strain gage on a rifle will spoil the accuracy.
1.2. You need a CMM to measure the ID and OD of a chamber.
1.3. Mounting a strain gage will cause your rifle to rust.
1.4. Strain gage systems cannot be calibrated, and the results are just a guess.
1.5. PRE is completely repeatable and reliable.
1.6. PRE is calibrated.
1.7. Claims to have 20 years of experience with strain gages.
1.8. Claims that strain gages don’t work outside a laboratory.
1.9 Quotes Ken Waters, the “father†of PRE to support his claims, when, in fact, Waters contradicts Hot Core.
1.10 Claims that a laptop computer and a $200 PressureTrace unit cost $3,750.
1.11 Claims that it takes about an hour to plug the PressureTrace into the computer, connect to the strain gage, and boot the computer.
1.12 Claims that measuring chamber dimensions with a dial caliper is just a guess at the dimensions.
1.13 Claims that the one and only way to calibrate anything is by direct comparison with a known artifact in the same units of measure. Can't explain how you calibrate an automobile speedometer using this method.
1.14 Claims that he is an EE, when, in fact, he is not.

2. Standard list of Hot Core self-contradictions—
2.1. Claims that you can use factory ammunition as a maximum pressure reference. Also claims that you cannot.
2.2. Claims that you need SAAMI standard ammunition to calibrate a strain gage, but that you don’t need it to calibrate PRE.
2.3. Claims that you cannot use chamber dimensions to calibrate a strain gage, but that you can use brass dimensions to calibrate PRE.
2.4. Claims that he gets four significant digits measuring brass with a micrometer, but the rest of us can’t get three when measuring a chamber.
2.5 Claims to be an EE, but can’t answer simple questions about analog electronic circuits.
2.6 Claims that PRE is calibrated, and accurate. Also claims that it is not, and that knowing actual pressure is irrelevant.
2.7 Falsely claims that the strain gage system is calibrated by repetitive firing of ammunition with an unknown pressure, failing to note that he proposed exactly this system for calibrating PRE.

3. Hot Core logical fallacies/half truths--
3.1 Hot Core can teach anyone to use a micrometer in five minutes, and it is a precise instrument. Since it is a precision instrument, and easy to use, it follows that the dimensions of a brass casing accurately and precisely reflect the pressure of a load.
3.2 Refuses/fails to provide any credible references or experimental data to support his assertions.
3.3 Argues that it is impossible to get adequately accurate chamber dimensions, because they involve a “double ogiveâ€. Obviously does not know where strain gages are actually applied, on the outside of the chamber over the middle of the cartridge case, and that the only chamber measurements needed are a single ID and OD.