quote:

Originally posted by DigitalDan:
... Been hoping somebody with some background in interior ballistics would check in a hang around for a spell,

Hey DD, Exactly what are you attempting to say?

quote:

...but if it gets too annoying I hope you would consider wandering over to http://www.24hrCampfire.com to join Ken Howell, John Barsness, Steve Timm and a long list of fine gents. ...

Just out of curiosity, does "howl" still "attempt" to talk down to everyone that doesn't kiss-up-to him?

Actually, I've found Ken Howell to be a perfect gentleman, very personable, and well informed. Since you resort to name calling, by calling him "howl", I assume that he must have said something you didn't like.

So Nosler uses PRE... so did Speer at one time. Perhaps they still do. Therefore, what?

I've never said that the method is totally useless. If you want to rely on it, knock yourself out.

To me, it is an economic decision: I want the highest grade of data I can get for the lowest price. PRE is about an order of magnitude worse than more modern alternatives, and costs about an order of magnitude less. I've done the math, and like the other methods better.

quote:

Originally posted by Joe Cullison:
JAL, you are correct about a modern 30-06 bieing able to handle more pressure than SAAMI allows and it is for the reason that you stated about some old rifles being around that might be up to the task.[QUOTE]


My point here was supposed to be that "Experts" in a Lab. can't know of personal situations, not to run down experts, who are quite handy to have around. :-)


[QUOTE]
I would say that someone that blindly follows the manuals by starting with the starting loads and carefully working up to where they are comfortable or to the book max, is being cautious. This is the correct method or procedure for the less experienced reloader and in no way makes them any less smart.Please allow the non-hot rods their path and they should allow you to have yours. Mutual respect.[QUOTE]


OK, I'm not a hotroder, I just have trouble expressing myself. My comments about blindly following any manual is for those who would think they must be safe when they start at a listed max. (This tends to happen I think where the word gets around that certain manuals are too conservative. (Again, not the publishers fault.) Litagation or not, I don't think anyone wants to see anyone blown up.
And apparently we can do that with underloads as well as overloads.


[QUOTE]
ricciardelli and everyone else, please forgive my earlier (2nd in this string) posting, I was sarcastic, and it was inappropriate.
Joe

No problem from me. Thanks for talking to me.
Even if I sound hard to convince, I take all info. on board, and think about it later. Hey, don't experts argue amongst themselves?
Regards,
John.

I hope Joe C. isn't getting worn out with the questions. Here are mine.

1) Might that SAAMI reference ammo you wrote of be available to the general public so we can "calibrate" our strain gages?

2) Are you aware of any other method for calibrating a strain gage, such as by using some kind of hydraulic system to pressurize the chamber to a known value?

Welcome to the board, Joe, and thanks for posting so much valuable information.

[QUOTE]Originally posted by denton:
Actually, I've found Ken Howell to be a perfect gentleman, very personable, and well informed. /QUOTE]

Denton, I am afraid you have only seen side of the person. I just hope he has less unprovoked discharges with his firearms than with his pen.

Joe, a true pleasure to have you around. Knowledge, combined with the ability and willingness to share it, is always like a fresh breeze.

As far as using PRE, maybe, on cartridges running at 65,000 KPSI max. But how are you going to use it for a 7x57, a 30/30 or a 223? FWIW, Dutch.

quote:

I just hope he has less unprovoked discharges with his firearms than with his pen.

Maybe I've been lucky... or maybe he has mellowed.

Hot Core, unfortunately I have zero influence at Nosler since our employment relationship ended a little over three years ago. I got caught in a downsizing. I still have contacts there and that allows me to keep up on most of the happenings there.
Even though they use PRE (as an additional check against the strain gauge data) they would most likely never discuss it in their loading guide. I think they believe that it is not something they want every reloader to use as a method.

denton, I believe that you are absolutely correct about the strain gauges being calibrated. The difficulty arrives when it is mounted on a barrel. Then the barrel gauge combination must be "calibrated" using the reference ammo and the system offset. Even though the strain gauge is calibrated the difference in chamber wall thickness, barrel material, barrel hardness, accuracy of mounting the gauge, gauge position etc can change the readings slightly. Thank you for the information, your knowledge and experience is welcome and appreciated.

I had myself a whole bunch of those sticky bolt lifts yesterday. I really looked hard after the first one and I had to assume that the locking lugs were galling. I always lube them but maybe they were getting rough. I was shooting the same load that I have been shooting for years in that XP-100 without ever having a problem, and with brass that is at least three years (20+ firings)old. I started testing some new "slower" loads (intended to reduce recoil and fatigue) and even though the loads were going almost 200fps slower, still, sticky bolt lift. So it seemed to me to be a mechanical and not a pressure issue. The bolt worked freely when just cycling the action. Then it dawned on me to drop the firing pin on an empty chamber, and whammo, sticky bolt lift, ON an empty chamber? Then I knew that it must be the cocking surfaces getting rough. When I got home and tore the bolt apart I found that the cocking piece retaining pin was broken and was allowing the cocking piece to rock out of alignment. The cocking surfaces got a polish and a lube just to make sure. A new cross pin was installed and the system is smooth as butter. I found a new slower load that shoots great, now I'll take a bit less punishment in a match and save some powder to boot.
I guess the lesson is, to fully investigate anything that is out of the ordinary. Pressure related, seemingly pressure related, or not pressure related at all.
Joe

Hey Joe, I understand. Darn shame though. Especially since it is the "very best" Pressure Detection Method "of all time" available for the reloader. But, it will just give us something to keep telling the Beginners about here - that works extremely well - and doesn't cost them a small fortune.

By the way Joe, it is obvious from the paragraph below that you have not seen "any" of denton's past posts on the HSGSs. What you just posted below is what has been related to him over and over without any of it ever sinking in. Not only did you stomp his toes, but you (to use a phrase he is familiar with) "blew him completely out of the water".

quote:

Originally posted by Joe Cullison:
... I believe that you are absolutely correct about the strain gauges being calibrated. The difficulty arrives when it is mounted on a barrel. Then the barrel gauge combination must be "calibrated" using the reference ammo and the system offset. Even though the strain gauge is calibrated the difference in chamber wall thickness, barrel material, barrel hardness, accuracy of mounting the gauge, gauge position etc can change the readings slightly. ...

One of the guys on this Board mentioned having purchased some factory Hornady Ammo. He wanted to use it to "Calibrate" his HSGS and got in contact with Hornady. They looked up his Lot# and provided the Average Range of PSI that Lot ran for them in a "Calibrated to SAAMI" system. I can't remember the exact numbers, but it was something like 58,5kPSI-63,5kPSI. Enough so he at least knew his HSGS was somewhere in the ballpark.

Do you know if Nosler would provide that same excellent information for their new line of ammo?

---

Hey Dutch, I thought you and howl were close personal buddies.

What they will say is that all of their ammo is within SAAMI pressure limits. They will not publish or in any way disclose measured pressures. They won't put it in the book either.

Great, I guess just call me "toe stomper". I hope denton wears steel toed boots.
Joe

Denton and Hot Core are big boys, they can handle their discussions.

Too bad the 4th of July is over. A guy could get free fireworks, just by asking Hot Core how to use PRE on a 223WSSM, and Denton about installation of strain gauges......

Too bad this format doesn't allow anyone to sell "pay per view"..... LOL! Dutch.

quote:

Just out of curiosity, does "howl" still "attempt" to talk down to everyone that doesn't kiss-up-to him?

Ah, Hot Core, I will not be drawn in, I will not be drawn in, I will not be drawn in...

Actually I've seen Ken get cranked a few times, all justified in my eye. He and I have disagreed a few times and I've found him to be perfectly polite about it. A few antagonists there have gone places with him that would have reduced me to a babbling touretts attack, but in the main his responses, polite as they usually are, be a far sharper blade than my gutter babble.

In regards the comment about having somebody around that knows something about IB, well, you can never have too many teachers. I find it's not always the facts that are wrong, it's the thickness of my skull. Sometimes when things are presented in a different light they manage to slip in under my "I Know Everything Radar". I even learned a thing or two from you.

I always keep 2, maybe 3 current reloading manuals on hand. As soon as I get a new one the old manual goes on the shelf only to be used for reference purposes. Once I was near batty trying to figure out why my .222Rem. Mag. cases were splitting in half. I hadn't reloaded for this caliber in about 20 years, then started back up using an old manual of about the same age. When I finally looked in a curent manual I was 2 full grains over max. That's a lot in a small case. There are many stories out there of reloaders doing this same thing. It's not worth running the risk. Just one mans opinion. Best wishes.

Cal - Montreal

My toes are fine. And I'm not the least bit blown anywhere.

We have a nice gentleman who used to work at Nosler, and who has joined in the conversation. He and I differ on a point. Therefore, what? I'll explain my point of view, and we'll have a nice discussion.

Joe, it is quite possible to have a meaningful calibration, without making a direct comparison to a standard in the same units of measure (i.e SAAMI ammo). If you think about it, it is impossible to get a direct comparison standard for miles per hour. They do not exist. Yet we calibrate speedometers.

Nor is it possible to get a single electron into a weighing pan, and compare it with a known mass. Yet we know the mass of an electron.

Nor is it possible to take a standard meter stick into space, and measure the distance to another galaxy. Yet we know the distance.

The methods for doing this are well covered at the National Institutes of Standards and Technology, at http://www.itl.nist.gov/div898/handbook/mpc/section3/mpc36.htm and at http://www.itl.nist.gov/div898/handbook/mpc/section3/mpc365.htm.

The energy conversion chain for converting PSI into voltage is based on the Poisson Ratio for steel, which is remarkably constant from type to type (less than 1,000 PSI difference between chrome moly and stainless), the inner and outer diameter of the chamber, the thickness of the brass wall, and its yield strength. All the required numbers are available to at least two, and often three signficant digits.

If you have all the right information, you can make a calibration without direct reference to SAAMI ammunition. Strain gage systems properly installed on rifles can be calibrated by the home user. However, it is a good idea to run some commercial ammo, just to check that you did everything correctly. If you're really desperate, you can lay out the $250 and buy some SAAMI ammo, though it will not produce the same pressure in your firearm that it does in a test barrel.

Joe,

I have a question about your opinion, if you have 1, about P.O. Ackley's loading data in POA #2. Having read a couple of copies of POA2 to pieces, I figured that I just had to have a 250AI. Try as I might, I never could get the performance levels cited by POA and I tried in 2 different rifles. Some of POAs loads seem not only hot, but dangerously hot, yet some folks continue to take everything POA wrote as if Moses had it in his back pocket when he came home with the 10 Commandments.

What do you think?

Jeff

quote:

Originally posted by Cal Sibley:
cases were splitting in half. I was 2 full grains over max. That's a lot in a small case. It's not worth running the risk.
Cal - Montreal

Cal, not having a go at you in any way, just wondering. Splitting cases in half? Sounds
extreem.
Were you using the exact same powder, same brand, or maybe one that was substituted with the same name?

So using an ADI manual about a year ago, they listed a max of 26.4g I felt comfortable with 26.5 in my rifle with around the best accuracy also.
Now a new manual is out, with Hodgdon having done the tests, and they recomend a max of only 25.5gr. So, with no compulsion to buy the new manual, what's changed? For me, nothing is changed, except the knowledge that Hodgdon's measurements are better/different.
My brass still lasts. (Famous last words.)

Someone in this thread i think suggested we can't be saying that a load is safe in our rifle.
Thing is a lot of us are saying a load (including factory loads) are NOT safe, (or desirable anyway,) in our rifles.

And I'm always hearing one can't tell the pressure by looking at a case, and I'm sure that's right. But I'm also sure after loading for about 45 years, that using a good manual or two, starting low, I can usually see a progression of pressure on the primers. Before you get ejector marks and hard extraction, I always seem to see where it's time to retreat.

EG Working up loads other day in a 458 WM I went to 0.5gr over the book to see what was what. Case came out easly, primer flatened somewhat, but said case was tight to rechamber.
Felt like it needed resizing already.
Well I only had that one of that load, and won't be doing another.
Guess what, the book was spot on !
Good one Hodgdon.
John L.

For some reason I am compelled to comment;
Strain Gage's are accurate, no question. The problem lies with the installation. The conversion from pressure to hoop strain assumes a long constant diameter section. On a rifle chamber one end is reinforced by the receiver, at the other end the thickness is increasing over the chamber neck. This makes calculating pressure inaccurate. Some "calibrationa" is required.
As to case head expansion; You are not reading pressure directly. What you are getting is an indication that the brass is reaching it's yeild point. Only a fool would not be concerned.
Good luck!

Hey Joe, I also understand about trying to keep some internal matters secret. Just makes the Hornady folks look better all the time for their willingness to provide the Average Pressure for the Lot.

quote:

Originally posted by Joe Cullison:
...it dawned on me to drop the firing pin on an empty chamber, and whammo, sticky bolt lift, ON an empty chamber? Then I knew that it must be the cocking surfaces getting rough. When I got home and tore the bolt apart I found that the cocking piece retaining pin was broken and was allowing the cocking piece to rock out of alignment. ...

Interesting example of how Pressure Indications can be fooling.

Yeah, "toe stomping" is a bad thing. I worry about doing it - ALL THE TIME!

quote:

Originally posted by Dutch:
You can always tell a Dutchman, but you can't tell him much

Hey Dutch, Is your buddy howl also a Dutchman?

quote:

Originally posted by DigitalDan:
Actually I've seen Ken get cranked a few times, all justified in my eye. He and I have disagreed a few times and I've found him to be perfectly polite about it.

I'll guess you had tears rolling down your cheeks and your sides were hurting from laughing as you whammed that in.

quote:

... you can never have too many teachers. ...

And you were doing so well, then got serious. Real nice to have Joe around (especially since he knows what he's talking about). Of course, the truth is tough on some HSGS full-of-beans fabricationers.

quote:

And you were doing so well, then got serious.

Don't call me Shirley!

260remguy, Ackley was never known to be afraid of building a load that sizzled. Not surprising for a fella that blew up more guns than I'll ever own. Don't know if it is the case with all of his data but a fair amount of it is dated so badly as to be worthy of censorship. Many of the powders he used back then were of slower burn rates than today so take his data with a very healthy dose of salt.

quote:

Originally posted by Hot Core:
Hey Dutch, Is your buddy howl also a Dutchman?

Hot Core, I'm pretty sure I have not made Mr. Howell's Christmas list for a number of years.....

But, seriously, have you checked YOUR ancestry? I wouldn't be surprised to find some hard-headed Dutch in there. Besides. Wooden shoes make for pretty decent steel-toe substitutes.... Dutch.

quote:

The conversion from pressure to hoop strain assumes a long constant diameter section. On a rifle chamber one end is reinforced by the receiver,

Yup. That's an issue alright. Also, corners tend to be squirrely for stress and strain, and you've typically got a corner on the barrel. I worried about exactly this issue at first. Ended up putting the gage 1/4" down the barrel, which I think might have helped.

quote:

at the other end the thickness is increasing over the chamber neck

Usually not. The strain gage is small, and is typically placed over the middle of the cartridge, rather than near the neck. At that point, you have a small, linear taper. OTH, if you're instrumenting a 223, there is no way to place the gage over the middle of the cartridge, because it's inside the receiver. In that case, you put the gage over the mouth of the cartridge as CIP in Europe does. It does give a different reading, so I think you end up treating that as a relative system--check some hot brands and don't exceed what they do.

quote:

I'm pretty sure I have not made Mr. Howell's Christmas list for a number of years

What? He sent me a nice box of chocolates... not.

260remguy, I hat to admit it but I have not read all of Mr. Ackley's books, just a portion here and there. I have used his book as a reference and looked at some of the data. When I was doing reloading advice (technical services) at Nosler I would always caution people that Mr Ackley's data was to be taken with a huge grain of salt, a couple aspirin, a big glass of water and a huge dose of moderation.
Partly because some of his favorite powders have gotten faster and partly because he liked to hot-rod things.

I would rather be whimpy on a thousand loads than reckless on one. For me it's all about my level of acceptable accuracy and I have never had to go to high pressure to get it. I can usually find something else that will solve the problem. But then my accuracy standards are probably less than some others. For most of my guns an average of three shots into 1" @100yds is good enough, some do better, some do worse which is just fine for a brush rifle or non-competition pistol. Some I find easily and some take a long time, but that is where the fun is, because as soon as I find an acceptable load for a gun I go play with something else.

Joe

quote:

Originally posted by Dutch:
...Hot Core, I'm pretty sure I have not made Mr. Howell's Christmas list for a number of years.....

I'd say that speaks right well for "you".

quote:

But, seriously, have you checked YOUR ancestry? I wouldn't be surprised to find some hard-headed Dutch in there. Besides. Wooden shoes make for pretty decent steel-toe substitutes.... Dutch.

I believe it is German-Irish, but it wouldn't surprise me at all to find some of the Dutch tossed in way back yonder. Are they known to be outstanding lovers of women? If so, I feel sure some of it is in there somewhere.

Nearly fell out of the chair when you mentioned "Steel-Toes", cause I had Steel-Toed brogans on when I typed the last post. I've found they do help create a faster sweat in this high Humidity.

quote:

Originally posted by 260remguy:
...Some of POAs loads seem not only hot, but dangerously hot, yet some folks continue to take everything POA wrote as if Moses had it in his back pocket when he came home with the 10 Commandments......

Mr. Ackley was one of the truly great Pioneers for Testing Wildcat Cartridges. His efforts are seen in nearly every cartridge developed since he documented his experiments. Lots of folks aspire to be as knowledgeable as he was, but few have the ability or means.

That said, I completely agree with DD and Joe concerning the Loads shown in his (outstanding) Handbook For Shooters & Reloaders Vol 1& 2. Lots of things have changed since they were written, with Powder being much different. I find the data interesting to ponder on a rainey day and the stories in the front of each Volume are indeed Classics. The trick is to remember that there is simply "better", more up to date, data available today.

Nothing wrong with using "most" of the Starting Loads and developing your own Loads. But simply copying a Load shown in a Manual without working up to it is simply a bad idea and can get you into serious Pressure Problems, almost as bad as a non-calibrated HSGS!
---

A Non-Calibrated HSGS = Reloaders Pyrite (aka Fool's Gold)

I know one of our posters has been looking forward to seeing that AGAIN and it does have a certain classy "ring" to it.

quote:

I know one of our posters has been looking forward to seeing that AGAIN and it does have a certain classy "ring" to it.

Sort of a dull thud.

Contrary to NIST, contrary to what Ken Waters wrote, contrary to what Ken Howell wrote, contrary to experimental facts... and written by someone who has exactly zero experience using the tool. No facts, no figures, no physics, just an unchanging and unfounded opinion.

Some things never change... Sun/moon... land/sea... fire/water... cat/dog...

...Denton/HotCore

What a boring refrain this is getting to be! IMHO, of course!

Im guessing that P.O. Ackley was not the only publisher of "HOT" loads from his era. In fact Ive got a few books with many loads that come quite close to his data, but people seem content to give Ackley the lionshare of that credit. I guess since he is gone that shouldnt bother him too much.

So let me see if Ive got this right, we have sub standard testing and data compilation processes from "the good ol days", the fact that every rifle is an individual, the fact that any alteration in, and of, any component or weapon has the ability to alter pressure itself, variations in powder lots, improvments in testing and data compilation methods and procedures spuring changes in load books, manual publishers repeatedly using the same max load data until just one of these many variations or tests exceeds the Saami golden yardstick and then respectivley droping the max...

Hmm, no I guess they are right, its all about the Lawyers.

And if that is what a million plus handloaders around the world believe, than the only question I have left for Joe is, how is it that they have lived this long?

Interesting thread with lots of great input.

And Joe, Welcome to AR..

quote:

Originally posted by 260remguy:
Joe,

I have a question about your opinion, if you have 1, about P.O. Ackley's loading data in POA #2. Having read a couple of copies of POA2 to pieces, I figured that I just had to have a 250AI. Try as I might, I never could get the performance levels cited by POA and I tried in 2 different rifles. Some of POAs loads seem not only hot, but dangerously hot, yet some folks continue to take everything POA wrote as if Moses had it in his back pocket when he came home with the 10 Commandments.

What do you think? Jeff

I think your evaluation of Ackley's top loads is right on target, not only for the .250 AI Savage, but a number of other loads in his books, both for "improved cartridges", and standard ones as well!!

At best, some of his recommended loads can be used as a starting point for developing loads for some of the strange or unusual rounds listed in his books.

I often use old manuals for starting point loads, particularly for old, obsolete rounds like the .32/40, .38/55, .45/90, .50/70, .50/140, etc.

Wstrnhuntr

"only question I have left for Joe is, how is it that they have lived this long? "

We have the strength and quality of the arms makers and the brass makers to thank for keeping all of us self proclaimed experts alive and relatively in one piece.

I'm sure a great many (if not all) of us have blown a primer or enlarged a primer pocket, had a hard bolt lift or some other classic high pressure sign. It is most often caused by some deviation from a published load or starting with a medium or even starting with a max load.
What we experienced at that time was a condition known as "Way over max pressure" and we should immediately thank the gun and brass makers for building in the safety factor that they do. Because their safety factor just saved our bacon.

We should all be glad that SAAMI rules our sport. If the government were involved in SAAMI's role like they do in avaition (FAA) we would all be shooting 30lb rifles with 1.0lb pieces of brass firing foam bullets at 50fps. The rifles would have to be pressure tested and certified every 10 shots. All components would have to be made from certified materials, cost ten times what they are worth, and have a 2.5 times safety factor built in by Professional stress analysis engineers.

We actually have it very good. And no matter what is ever printed someone out there is going to push the envelope. Some might even call them pioneers. I think I would rather be a pioneer in a different, less potentially hazardous area.

Joe

Joe,

Your points are well taken and I find your rather unique insight a sensible and refreshing variation from the norm on this subject. As inaccurate and unreliable as they may be I would also have to give at least some credit to the reading of "the usual pressure signs" for keeping our collective bacon intact over the years. And as a handloader, I believe that good information, such as a variety of carefuly compiled load data and knowing what to look for, such as velocity spikes, flattened primers, and also bad advice, can also be very usefull when getting home from a shooting session in one piece is the ultimate goal. Personally I find the malcontent for maximum published loads on threads such as these quite irresponsible and thoughtless. It is not what begining handloaders need to be reading.

On the subject of the strength and quality of arms makers, what if any is your opinion of investment cast actions? I see them getting an awfull lot of criticizsm and yet I myself am unaware of any specific problems that may have arisin (sp?) due to a lack of strength, and yet the house some of the most intense cartridges on the market today. Seems to me that a good track record is usualy more credible than speculation. Perhaps I am just uninformed though.

Thanks for the replies, Byren AKA Wstrnhunter

MarkL Please forgive me for not answering your questions sooner. I must have missed your post in this string the first time I read it through.

SAAMI reference ammo is available to the public. I do not have their contact information on hand at the moment but I'm sure a short internet search would turn up the information.

I am not familiar with any other method of "calibrating" a strain gauge but my experience with a strain gauge was limited to the Nosler Ballistics lab.

Wstrnhuntr
I too use, the traditional pressure signs to keep an eye on things. They can be helpful as a guide, used in conjunction with the best and most current data available, careful cross referencing, theoretical data and everything else that might keep us in one piece. We have to use everything we can to be safe. I think that primer flattening can be an excellent indicator of relative pressure, light, medium, or better back off a bit.
As long as we wisely use every tool we can and proceed with caution, we will mostly stay out of trouble.

I shoot T/C's a great deal and I have no problems with the investment cast frames at all.

Dutch,
The PRE works well on the cartridges you mentioned also, due to the reason that it should be used as a relative measurement. It should compare factory ammo expansion to the expansion of your test load in virgin brass. It would be wrong to use it as an absolute value such as .005" as a max. It is all relative to the individual chamber, cartridge, etc.

Joe

Joe, with all due respect, I disagree.

PRE can only be used with similar pressure levels, with similar brass, with similar powder burn rates, bullet weights....

Within that limited window, it may be better than reading tea-leaves. But I am not convinced.

However, it is simply of no use, whatsoever, in tight chambers, for "under maximum pressure" loads, for wildcats, etc, etc, etc.

If I want to load my 223WSSM with 80 grain bullets at under 53,000 PSI in a "match spec chamber" (and I do), PRE is simply useless. WSSM brass simply does not move at those pressures.

Or, looking at it from another perspective, exactly in those cases where you do NOT have the needed references and need a pressure tool most, PRE is useless. JMO, Dutch.

quote:

Originally posted by Dutch:
Joe, with all due respect, I disagree.

PRE can only be used with similar pressure levels, with similar brass, with similar powder burn rates, bullet weights....

Within that limited window, it may be better than reading tea-leaves. But I am not convinced.

However, it is simply of no use, whatsoever, in tight chambers, for "under maximum pressure" loads, for wildcats, etc, etc, etc.

If I want to load my 223WSSM with 80 grain bullets at under 53,000 PSI in a "match spec chamber" (and I do), PRE is simply useless. WSSM brass simply does not move at those pressures.

Or, looking at it from another perspective, exactly in those cases where you do NOT have the needed references and need a pressure tool most, PRE is useless. JMO, Dutch.

Hey Dutch, I'm certainly not answering for Joe as I feel sure he will respond.

Just want to say with all due respect, your thoughts on PRE are totally wrong. As always, it is the very best Pressure Indicator available for the average reloader when done properly.

It also works just fine in "tight chambers", for "under max pressure Loads" and will also work for "Wildcats" once the person has gained the proper experience with it.

CHE won't work with all cartridges because some of them have SAAMI Pressure limits below the threshold for the Case Head to Expand. If it does, you are way beyond where you should be.

PRE on the other hand works(and works great) with every cartridge. Always has, always will - when done correctly.

PRE will not work properly when the person attempting to use it is Neck Sizing cases.

Hot Core I have to agree with Dutch on this. I do admit PRE is a aid in evaluating loads, and I use it as such. I don`t think of it as telling me the pressure so much as telling me what the brass`s reaction to the pressure is though, especially if the brands/lots differ.

There are to many variables in the differnt brands of brass to rely on expansion as a pressure indicator, thickness and hardness for example. I think the PRE reading on a factory case is likely a good indicator of how much expansion is safe in a certain chamber and more is likely to be stretching the elastic limit of the brass, but as far as pressure it says nothing.
JMHO........

Test was done with a Mitotoyu electronic blade micrometer, clamped to a granite inspection plate, so that measurements were made exactly on the pressure ring. The procedure followed for the measurement was the one outlined by Ken Waters in "Pet Loads".

The blue dotted lines are the 95% Prediction Interval, i.e., 95% of the data will fall between them. 5% will fall outside.

The red lines show the span of pressure values that could easily be represented by a PRE of .4980". .4890" could easily represent actual pressure anywhere between 44 KPSI and 73 KPSI.

Dutch, you have me a little on this one since I have not personally tried reading PRE in a WSSM or any other short, thick walled casing (especially in a match chamber) So I cannot say if it works or not.

Are you trying for a 53,000PSI load or a less than max pressure load that shoots well? Just what is your goal? If you are getting a less than max pressure load and it shoots great, then who cares what PRE, CHE or anything else says. If you would like an idea of what pressure you should be getting with your load run it through Quickload and be sure to include the case capacity in grains of water. it will at least give you a theoretical number.

A very wise man once told me that "if you have a safe load that performs the way that you want it to, who cares exactly what the pressure is?" He also said if you get the kind of accuracy you want without doing all of the little brass prep tricks, runout measurements, neck turning, then why bother? Just load and shoot. Sometimes it's just not worth sweating the small stuff. If it is not working for you then don't do it.

If you are the kind of person that really gets into the fine details, then by all means have fun. But thanks for adding your personal experience to the conversation. Perhaps we can all learn from each other. PRE is just one tool available to us and should be used in conjunction with every bit of information we can gather.
Joe

OK denton, that is a cool graph, but where is the rest of the information? What gun? what cartridge? what is the chamber wall thickness? what is the size of the brass before firing? what brand of brass? how many firings on the brass? what was the hardness of the brass? was one piece used for the whole graph? did you use several pieces with one firing each that had been match prepped and weight sorted? What is your sample size?

The point I'm trying to make is that without every detail you can possibly include, the story is incomplete. This kind of information should be presented with documentation of the details that show that the information comes from a carefully constructed scientific experiment, and where possible and necessary, double blind.
It is a ton of work to do a test in that manner, so I won't be posting much of that kind of data. I'd rather spend my time loading and shooting.
Thanks for the cool graph.
Joe

Answers to your questions:

Finnish Mosin M39
7.62x54R
Have that data, but not going to dig it out... irrelevant to the Waters PRE method
Irrelevant in the Waters PRE method
S&B
Two. One with a factory load, one with my reload
Unknown, and irrelevant to the Waters PRE method
No
Used several pieces, no special prep
One dot on the graph for each casing

Double blind studies are nice. The medical establishment loves them, because the prevent the placebo effect. Since we don't have that here, a double blind study isn't called for.

You can see photos of the test setup, and a more thorough discusssion at http://www.shootingsoftware.com/tech.htm.

This was a test of the Waters PRE method, using one type of cartridge. The outcome of the test was that PRE does yield some information, but it is mixed with a considerable amount of random error. The amount of random error is indicated by how widely scattered the points are around the line. The breadth of that scatter is one of the key "figures of merit" for a measurement system. That figure of merit for PRE, in this particular case, was almost exactly an order of magnitude poorer than that of a strain gage system.

Anyone who wants to replicate the experiment can, and I would welcome seeing those results, whether they confirm my findings or not. I would love to see this replicated several times, by different people, using different cartridges. The procedure is this: Prepare about 10 matched pairs of cartridges. The first pair contain a minimum charge, and each pair after that contains half a grain more than the pair before. Shoot all 20 cartridges (10 pairs) in random order. Measure the PRE's and graph them vs. charge weight. If you get widely scattered points, then you confirm my findings. If you get points very tightly clustered around a central line, then you have a result contrary to mine.

I have no love for strain gages, and no hatred of PRE. In fact, if you read through the article, you'll see that I point out a method for getting much higher quality data out of PRE, but at considerably increased testing cost. It's a simple economic decision: What's the best quality of data I can get, for the least cost and effort? I have a pretty good solution, and would be very pleased to have an even better one.

Anyone who does the nitty gritty experimental work to show me a better method is going to get a big pat on the back, and a hearty "thank you". This isn't a religious or political discussion. It isn't about who is right. It is about what is right.

denton,
Thank you for the prompt and very complete response. I can see now that you have indeed done your homework.

I will read the Waters information and see what he has to say about the matter. I'm not a big reader but this looks like a good one for my continuing education.
So much to learn and so little time.
Shooting or reading it's kind of like the struggle I have between buying a safe or another gun. Tough choices. I'll read your article also.
Thanks
Joe

quote:

Originally posted by Joe Cullison:
... that is a cool graph, ...

Uuuuh Joe, You are being led down the path and being severly mislead by the chart and the statements. The chart is about as valid as clinton "guarding" an intern.

The entire thing got started because denton thought he could "prove" CHE & PRE did not work at all. As a result, all the alleged "data" is skewed with his intent to make it look bad.

denton even "skews" Ken Waters words as "interpretations of what he(Mr. Waters) meant" in denton's mind.

He had me fooled for about 6 months when he first mentioned he had a HSGS. But, the more questions you ask him about it, the more you realize his answers indicate his actual knowledge using them is tainted by his desire for them to work perfectly - without Calibration to a known Standard or knowing the proper Chamber Wall thickness.

Just saw another thread where he posted a load as 54.4kPSI, with no Range given for the Pressure. As if his non-calibrated HSGS is accurate to PSI in hundredths. Pitiful!

Just bear in mind what you read in his posts, and what is reality, are generally mutually exclusive. But, I'd imagine you will pick up on it very quickly, whether I point it out or not.

Hey Ol' Joe, Perhaps we are not as far apart as you think. I'll just skip to the below and see if we can actually agree.

quote:

Originally posted by Ol` Joe:
... I think the PRE reading on a factory case is likely a good indicator of how much expansion is safe in a certain chamber and more is likely to be stretching the elastic limit of the brass, but as far as pressure it says nothing.....

I agree with all your statment until you got to, "but as far as pressure it says nothing".

1. Since you mentioned it is a "Factory" case(I believe you meant cartridge), I would guess you will agree the Factory cartridge is intentionally manufactured so it is, slightly less than or meets the Average SAAMI Pressure Specification?

2. Let's say the Factory cartridge above is a 308Win with an Average SAAMI Pressure of 52,000cup as listed in most any Manual.

3. As an example let's say you fire a box of cartridges and find the Average PRE for those cases is 0.4720"(made up number). You now have a "Comparative Benchmark (Pressure Indication) Standard"(CBS).

4. Then you P-FLR the "exact same cases" so the Pressure Ring is Resized(Neck Sizing will not work for this).

5. You return to the Range and fire your Reloads.

6. As the PRE approaches the CBS of 0.4720", it indicates to you that the Pressure is either slightly below or at the same Pressure as it was in the original Factory cartridge. Do you agree?

Now, depending on the specific Primer, Powder and Bullet, the actual Velocity might be less, the same or more than those original Factory cartridges. But, by measuring the PRE, and comparing it to the Factory Cartridge Average PRE, you know your Pressure is at or below 52,000cup.

Do you agree?