quote:

Originally posted by jackfish:
There are "NO" problems associated with ballistic strain gauges if they are used appropriately.

Wrong AGAIN! There are four basic problems with the Haphazard Strain Gauge Systems. They are all listed in the thread for anyone to see, along with Dr. Oehler's responses.

quote:

The problems associated with inappropriate use and their limitations with appropriate use are well documented for all who endeavor to employ such instruments. It is also well documented that ballistic strain gauges properly set up sans calibration can determine the pressure in PSI of any ammunition in a specific firearm within a reasonable amount of error.

I do believe we are in agreement. They are very well documented:
1. In the thread I posted which clearly explains all the problems.
2. Marketing hype.
3. And by a fool who thinks driving a "Live Primer" out of a Case with a Sharp tool is a great idea.

quote:

To say they cannot function outside of a lab environment is as inane as stating that a strain gauge will not work without calibration.

Never said they would not work outside a Lab Environment. The only problems is the data provided by them is as useful as parachutes on cows. Yes you can use them without Calibration and you end up with "unknown" Pressure - just as said in the thread.

quote:

I will now join the many others who have chosen to ignore your rants. ...

Once again we agree. Is is the best thing for you to do since you are not making any good points in Defense of the HSGSs.
-----

I was speaking with a buddy in Califoney last night and he said there are still a few folks who have been " dentoned " into thinking there is an accurate CUP to PSI conversion. That is also covered in the thread where Dr. Oehler "verifies" there is no accurate conversion. Or as I prefer to say, those who believe anything denton has to say is Full of Beans.

quote:

Originally posted by seafire2:

quote:

Perhaps Hot Sh$t and Gore are related!!!

Teancum,

I hope this doesn't tarnish my reputation too much....

My grandmother and one of Al Gore's grandmothers were sisters!!!! so he is actually a second cousin to me...

but I never would vote for him anyway....

I've met him a few times at a couple of family reunions when I was a kid.... .back when his dad was a state senator.. who did give me a recommendation to the Air Force Academy... but I ended up not going since I wore glasses,and couldn't end up flying.. and I always wanted to be a pilot in the worst way...

Sorry Seafire2

Any slams were not intended for you by any means and if any of that splashed on you, I apoligize.

All slams were intended for Hot Sh$t and his vast suppository of knowledge that no one dare challenge or disagree with. Pitiful that he is so dead wrong all the time and dangerous to beginners. Posters like this need to be called out for the misinformation that they sprew forth from who knows where. Wait a sec. On second thought that ignore button is wonderful and makes for a much more enjoyable board where opinions and experience is shared and either used or discarded without all the drama.

Hot Core,

In my observations and comparisons between your claims and Dr. Oehler's statements, I must assume that you are throwing the baby out with the bath water when critisizing the usefulness of HSGS.

Yes, Dr. Oehler left the cat out of the bag when he stated that the strain guage is not capable of consistantly accurate measurements below the "50,000" psi levels. This is due to the a less measurable stress on the barrel at lower pressures. You still get measurements at lower pressures, but the accuracy of those measures is less.

As a reloader, my main concern is not with the accuracy of a lower pressure load, but knowing when my rifle is reaching max pressures with my reloads.

According to Dr. Oehler, it seems that as pressures approach the max levels, the accuracy of the HSGS increases due to more measurable strain. The more strain you have to measure, the more accurate the measurement. So, the HSGS does in fact provide a more accurate and safe set of data when trying to determine a safe or near max load in a particular rifle.

That said, the data is still similar to a "Go-No Go" gauge. CHE method is the same thing; it doesn't tell you what the pressure is, it just gives you an idea when to stop.

The Lyman # 45 or 46 manual explains how to use the CHE method with some slight variations from your technique. The say to use once fired cases, take your head measurement and if there is any measurable differnece after future firings, then pressure is excessive. Then, in their #47 manual, they drop it from the publication. Finally, in the Lyman #48, they dedicate a paragraph to the CHE method with some reference to your use of it and their previous of its proper use.

CHE is a "go-no go" method with less information for the reloader than the Oehler system. Neither one is perfect for a professional ballisticians needs, but for the average Joe Schmuck who likes to reload, I would contend the Oehler system provdes a better picture of what is going on in their rifle.

Regardless of the setting, in a Ballistics Lab or on the tail gate of a pickup, a PSI is still a PSI, and the only time I need highly accurate information regarding pressure is before I start to do damage to my gun or myself. This is information that Dr. Oehler claims to provide with his HSGS, and nothing more.

quote:

Teancum,

I hope this doesn't tarnish my reputation too much....

My grandmother and one of Al Gore's grandmothers were sisters!!!! so he is actually a second cousin to me...

but I never would vote for him anyway....

Seafire!!

Never underestimate the power of genetics!! It seems you and your cousin are equally capable of finding the issues that make people crazy!! For Al it's global warming, and for you, it's this thread!!

Still, I enjoy both you and your cousin. Keep up the good work!!

quote:

Originally posted by mike_elmer:
Hot Core,

In my observations and comparisons between your claims and Dr. Oehler's statements, I must assume that you are throwing the baby out with the bath water when critisizing the usefulness of HSGS. ....

Hey Mike, Did you read what Dr. Oehler has to say in the thread in response to my questions?

Back when the M43 was initially released, I was as excited about it as could be. Looked like an excellent tool for experimentation with Reloading.

Then a fellow got one on the old "Shooters" board who went by OKShooter. It was great to have someone to ask questions about it that actually had one. Only real problem was - I already had a good many years experience with Strain Gauges as a Product Evaluation Engineer and was able to ask some direct questions concerning their use. The same questions can be found in the Link and the answers still indicated they are not adequately addressed (in the Owners Manuals) nor from the guy who put them on the market. I have a lot of respect for Dr. Oehler and commend him on the way he did answer my questions. But, the problems are still there.
-----

If you want to take a shot at the problems, I'll be glad to accomodate you with the questions. If you have not worked extensively with strain gauges and electronics though, the real answers can be frustrating.

For example:

quote:

As a reloader, my main concern is not with the accuracy of a lower pressure load, but knowing when my rifle is reaching max pressures with my reloads.

That is a valid concern and the reason I'm such a fan of CHE & PRE.

However, since we are talking about the "Haphazard" Strain Gauge Systems(as Dr. Oehler described them) I'd ask how do you know when you reach the Max Pressure by looking at the HSGS data?
-----

If you would rather do this through PMs, send me one. Or if you would like to talk it out, PM me your phone number and I'll call you. Let me know when it is convenient for you.
-----

quote:

CHE method is the same thing; it doesn't tell you what the pressure is, it just gives you an idea when to stop.

Yes indeed it does!!! CHE(and PRE) does not mislead a user with inaccurate pressure readings designed to give the impression that they are accurate to 1psi. If you read the Link, Dr. Oehler really nuked the accuracy potential.

quote:

CHE is a "go-no go" method with less information for the reloader than the Oehler system.

I must agree that CHE(and PRE) is an excellent - "go-no go" method - but disagree that the information provided by ANY HSGS (outside a Ballistics Lab) has useful information. Way too many chances for Error and way too many Fudge Factors tossed in to make them work at a randomly picked arbitrary value.

quote:

PSI is still a PSI, and the only time I need highly accurate information regarding pressure is before I start to do damage to my gun or myself. This is information that Dr. Oehler claims to provide with his HSGS, and nothing more.

The crux of the problem is - the User doesn't have a clue about what the REAL PSI happens to be - but he has been "lead to believe" that what he sees on the display is Accurate, when it really isn't. As a Reference, check the Link to Dr. Oehler's words on how much Variation he has seen in the HSGS data.

I make these comments because the posts here are read by many new comers to reloading, and some of the things people posts could lead them to dangerous practices. I have reloaded for thirty plus years and still consider myself a student, but I have learned a few things from personal experience, more from reading and listening to the experiences of others. The most important thing I have learned is that reloading is an art, not a science.

The methodology one adopts should be appropriate to one's purpose. If your purpose is to make some reloads for your 30-30 for hunting or target practice, you can achieve your end by purchasing a Lyman manual, looking under 30-30, 170gr round nose bullet, and looking at the bottom of the listing therein for the most accurate or factory duplication load. You'll do just fine if you use the components listed and follow the basic instructions.

On the other hand, if you are reloading for some wildcat or a older cartridge like 7x57 like I did when I started, you will need all the information available to you. You will need several manuals, preferably one from the maker of the bullets you like and one from the powder company you like plus a general manual like Lyman.

If you shoot a European cartridge, like 9.3x62 or 7x57, its a good thing to get a European manual for pressure and velocity data. Data for many of these cartridges is held down in US books because of older rifles in these vintage cartridges. European manuals tend to make adjustments for these issues. Read what all the manuals have to say about reloading technique.

In addition, you should have a chronograph. Without a chronograph you are just guessing at what is happening. (Some have suggested here you can extrapolate velocity from bullet drop, and you can, but you can't do it on a 100yd range, and you'd better be a damned good shoot shooting in zero wind conditions.) If you don't know how fast the bullet is going, you don't know squat about the load or your rifle. You can't tell if its a fast rifle or a slow rifle. You can't tell whether you are below the book, on the book or over the book values. The price for a basic Chrony is a cheap ante to get into the game.

Contrary to what some have said here, there is a direct relationship between pressure and velocity as Alf, Jackfish and others have noted. A rifle/bullet combination is a one stroke engine. The bullet is the piston and the bore the cylinder. The powder is the fuel and burning it makes gas which pushes the "piston" down "cylinder."

As Alf noted and it is well accepted the peak pressure in a rifle bore occurs before the bullet reaches its maximum velocity. This phenomena together with the different burn rates of powder (octane) is why velocity alone is not fully revealing. Without reference to manuals and other observations from shooting such as sticky bolts (bad news because if you are there, you are way over "redline"), loose primer pockets, primer strike indications and primer shape, you cannot make a SWAG about pressure in the absence of stain gages or pressure barrels.

We must be aware that different standards exist in the US and in Europe; we must be aware that different manuals use different components; and we must be aware that the data in manuals reflect their statistical analysis of the results of their test. In sum, you have to use judgment regarding manual data and apply it to your situation.

My personal observation based upon my experience attempting to establish pressure limits for my 9.3x62 was based upon my assumption that the weakest link in the chain was the case and its components. My "scientific" approach was to assume that if a standard, non-magnum case could withstand eight discharges with a load without loosening the primer pocket or suffering a thinning of the case wall at the pressure ring, a point about three-eights ahead of the extractor grove, then the load was safe for my rifle.

I selected three powders which I felt were candidates for a propellant and made up five test loads for each near a US max (I had already tested this rifle sufficiently to determine that it was a "fast" rifle.) I fired all of these and determined that one would never be able to reach the velocities I was seeking within the pressure limits. (It was the fastest of the powders being tested.)

I loaded up a second test of five loads with the two powders at a bump higher. This indicated that the next fastest powder would not work. Thereafter I concentrated on the last powder, which was the slowest of those selected. With this powder I continued to increase my velocities until I reached what I felt was a reasonable limit which was about five grains above the US limits. (This was consistent with European data/info indicating pressures for the cartridge limits in old Krags and Model 96 Mausers.)

At this point, I started my final tests, loading five rounds with my "max" and after the fifth test, sectioning one of the cases. This case showed no signs of loose pocket and no sign of narrowing at the pressure ring. I then fired two more tests, and sectioned another case. I found no sign of loose pockets and no sign of narrowing at the pressure ring. I fired the two more tests and
found the barest hint of a pressure ring and at this point the pockets were getting loose.

I concluded that my load was "safe," ie, could be loaded eight times, in this rifle. I also concluded that for those with only a chrono, that this method is an alternative we can use to establish safe loads without expensive equipment. It takes only a couple of pieces of brass and a dremel tool.

I hope that this provides the newbies some ideas and you old guys something to think about. Kudude

PS: The pressure ring measurement method of determining safe pressure has been totally rejected by most "experts" to include Ken Waters and Ken Howell, if my memory serves me correctly. The current line from "experts" is follow the book or use a strain gage which is why the method I used above is a viable alternative for those of us without strain gages or access to ballistic labs. K-d

/

quote:

Originally posted by ScottS:
seafire2,

How long have you been reloading? Your post is very old news!!

Oh I started my first reloading the Tuesday before Christmas.... didn't have anything better to do.. so I thought I'd go out in the garage and try my luck....

quote:

Sorry Seafire2

Any slams were not intended for you by any means and if any of that splashed on you, I apoligize.

Teancum,

No worries.. My response was more a source of humor than anything else.. actually I'd rather be related to Rodney Dangerfield than Al Gore.. at least Rodney is trying to be a comedian...

I didn't take that as a slam at all...every family has a few clowns in the woodpile.. that side of my family just happens to have a high profile clown...

then on my other side of the family, ( mom's) we are related to Senator Byrd of WVa.. he is my mom's second cousin, so that would make him my 3rd cousin....

That should impress my buddy Mike Elmer tho... he likes all those democrats... but he is a pretty good guy for voting democrat and needing a haircut...

Naw, I don't take such stuff overly serious... some one has to be related to some of these bozos.. might as well be me... believe me, being related to both of these guys and a quarter will get me a cup of coffee whereever they sell it for a quarter...

quote:

Originally posted by ALF:
Kudude:

The first internal combustion motor = The gun !

Why is the method I proposed valid ? Because of the physics that rule the functioning of the internal combustion motor. The physics underlie the very principle to which modern computer based load programs and the Powley computer is founded on.

What is clearly understood though is that each gun is an individual and that data derived from calculations are not directly applicable to that gun..... it's a no brainer.


In any load with any gun the velocity with which the projectile ( piston) will be propelled down the bore ( Cilinder) will be dependent on the pressure generated by the combustion of the propellant for that particular gun and set of particular components.

In a typical well worked up load with very little inter- shot variation in velocity the pressure value variation will likewise be small.

Every incremental increase in propellant mass for that specific combustion chamber and projectile should give a gun/ component specific predictable rise in velocity, the rise will be necessity not be strictly linear but within the normally used "safe" window of operation the relationship between velocity and charge mass is close to linear as shown by measuring velocity and calculating the V/C value.

If suddenly there is a increase in velocity in excess of the expected trend it can only be at the hand of increased pressure assuming that the projectiles used are uniform and that is the cue to be careful.


Sudden unexpected negative deviations from the trend assuming accurate velocity readings can occur in certain circumstances, such as when propellant quickness is too low for the expansion volume used ( ie using to slow a powder for a particular expansion volume and secondly in the case of "powder quenching", in this case the whole charge mass does not burn and a large or variable part remains )

This is some vintage stuff (1965) from DuPont showing the principle:



What we see is that the calculated "load line" approaches the true or dynamic V/C line and for some distance lies in close proximity to the true V/C line, this represents the "safe window" in terms of pressure utilization

The same from Somchem more recently published in the 80's:


And from Dupont 1965: Showing the relationship
between Mean barrel pressure and bullet kinetic energy. The relationship between projectile kinetic energy, expansion volume and mean barrel pressure gives some interesting graphs.

The problem with extrapolating peak chamber pressure from mean barrel pressure is the problem as the relationship between MBP and PCP is anywhere from 1: 2 to 1:3.

Interesting stuff. but leaves some questions to be asked....(not criticisms, but genuine questions).

1. Where are the charts that show simultaneous comparisons (correlations) of pressures and velocities?

Also, what were the pressure extremes along the way...in other words where are the scattergrams of the actual shots and their pressures/velocities as fired prior to aggregation?

As you may or may not agree, I believe it is not the average pressures (shown by those nice smooth curves) which get handloaders into trouble, but the extreme variations which may occur along the way.

I would also note the degree to which, at the upper loadings including right after the point labelled as optimal in one chart, the curve then begins to go almost straight up. Until then, velocities MAY have been more or less predictable, but immediately after they sure aren't, so if velocities are dependent almost totally on pressures as some contend, are the pressures safely estimable at that level?

Doesn't appear so to my reading of the charts. At that level, I'd be doubly worried about any exceptions on the high side of average damaging something (me for instance), even though the "average" pressure might be quite safe if there was any assurance of not exceeding it.

I have other questions too,but they are likely too complex for us to get into here, and deal mainly with burning/pressure characteristics of the powder designs and the volumetric vessels within which they are intended to burn and the piston weights they are intended to move. That would get us off into such items as chemical composition, powder granularity/porosity, shape and density, detonation thresholds,and a lot of other items we could probably never cover here (But that may all be relevant to the consistency of powder burn rates in different sized combustion chambers behind different weight bullets)...

Anyway, I agree there are times when a chrono can provide useful added info, but personally, if I need a hotter load than is clearely non-destructive to my brass and rifle(s), I will go to bigger volume cartridge cases, designed to use more of an appropriate to bore volume propellant, rather than risk mis-reading what is for me an inadequate amount of info.

And I will let my fired brass tell me when it is showing more signs of stress than I feel safe with. I know that will vary with every lot, perhaps to some degree with every piece of brass I fire, but it will be an actual reading of an actual load in something other than "modeled" circumstances.

To each his own, I guess. If that makes me an old fuddy-duddy rather than "cool, modern, and with-it", C'est la vie.

Best wishes.

Well now off the humor end, and back to the subject of the thread...

I think a few folks have misunderstood me on my suggesting where the chronograph fits in within the reloading circles....

I think it is very important in helping you know exactly what your loads are doing....

I have to admit, most of the time in load developing, the very last thing I do in load development is pull out the chronograph...

I use manuals for approximations of velocity...
however like the point I was showing.. BLC 2 was waaaay off base, despite several manuals claiming a lot higher velocity than my rifle was delivering....

This was to be used for calling coyotes... and being about 350 fps short of the MV I was thinking I would be getting would have meant a lot of missed shots and the shooter busy wondering what the Hell????

When I develop a load, and it proves give me the accuracy that I want....The very last thing I do is pull out the old chrony...

Now the chrony will tell me how close to specs my velocity and load is with that rifle...

Then I do my usual, set my zero to be 3.5 inches high at 100 yds, and then knowing the height of the intended game ( coyote in this instance) I have a strong working knowledge on exactly how far to expect my POINT BLANK RANGE to be with that load...

My priorities are accuracy first.. then we worry about velocity.. velocity essentially tells me what my intended trajectory is going to be....

But that also tells me accuracy along that trajectory path...

Getting 350 fps less velocity, than listed in the load manuals, means I would be missing a lot of shots... AND I am a firm believer that an ethical hunter, knows or has a strong idea of where that bullet might be going IF HE MISSES HIS TARGET...

lets face it, there can still be people out in the areas we are shooting.. OR these cartridges have a long range to them.. even a 22 LR with an MV of 1200 fps, can still travel up to 1.5 miles....

knowing what my MV is out of my rifle, also helps me be a more ethical and consciencious shooter and hunter in the field...

because one of my biggest questions and pet peeves, is when I ask a fellow hunter, "if you miss your target, do have any idea where your bullet is going to go or land??" Most don't have a clue....

but if you know your MV and you know your maximum point blank range.. at least you are not just going to be out in the woods and slinging lead...

to me, that is the importance of a chronograph..

you know, and your aren't just guessing or hoping you know...

I understand Kudude's desire to help the Beginners, Rookies and people like alf, tater-tot, and jackfish, but he has some facts confused. I'll just pick two.

quote:

Originally posted by kudude:
...Contrary to what some have said here, there is a direct relationship between pressure and velocity as Alf, Jackfish and others have noted.

Hey Kudude, The problem with this line of thought "misleads" the Beginners, Rookies and people like alf, tater-tot, and jackfish, into thinking it is possible to just keep dumping in Powder until some arbitrary velocity found in a Manual is reached and there will NEVER be any Pressure Problems.

The truth is there is NO "Standard Pressure at a Specific Velocity" associated with a specific Case, Primer, Powder and Bullet combination. The actual Pressure may be:
1. Much less than expected.
2. Less than expected.
3. The same as was expected.
4. More than expected.
5. Much more than expected.

quote:

PS: The pressure ring measurement method of determining safe pressure has been totally rejected by most "experts" to include Ken Waters and Ken Howell, if my memory serves me correctly. ...

I can understand that howl would not have a clue concerning CHE & PRE, so I'll accept Kudude's comments concerning that fool. However, Ken Waters(as well as Bob Hagel, Gary Sutton, and many other great Reloaders of the past) have ALWAYS written their articles and books concerning Loads they Developed when using CHE & PRE. They did also chronograph the Loads, but only to add that information to the article. They NEVER once mentioned using a chronograph as an indication of Pressure for one reason - they know/knew a chronograph only tells Velocity and is not indicitive of Pressure.
-----

In defense of the (mostly worthless) Chronograph, it can provide three useful things:

1. For l-o-n-g distance Shooters, once you have a couple of accurate Loads, it can tell you which one has the lowest Standard Deviation. It "might" help the Reloader determine if that same Load happens to be the most accurate at distance. But, as always we actually need to shoot the Loads to see which is the most accurate.
2. For a person who has used a chronograph for a long time and uses every Pressure Indicator available as they Increase Loads, they will notice the Velocity does not always go "Up" when it reaches a specific(and often potentially Dangerous) Pressure Level. If you are paying attention to the other Pressure Indicators, then there is no reason to reach this level of Pressure.
3. They stimulate the economy.

Best of luck to all you folks.

/

[/

HotCore,

Are you seriously suggesting that there is not a direct correlation between pressure and velocity?

Kudude

HotCore,

When we started loading, there was very little knowledge about what actually went one inside the case and barrel when a shot was fired. It was only with the development of strain gages and high speed measuring equipment that data could be obtained on pressure over time in the barrel.

Studies using these methods showed that was a peak pressure and an average pressure. It is the peak pressure that one has to worry about. As the bullet moves down the barrel in increases the volume of the "cylinder" geometrically; therefore, there are one or more pressure peaks reached during a shot. Alf has described the current thinking on this process.

I think we have all agreed that the danger is when, for whatever reasons, max pressure is reached unexpectedly. As Alf and others have indicated this is thought to be the result of increased "front" end burn as the result of increased pressures.

For reasons identified by another poster regarding not only differences in different lots of brass, but the same lot after different firings, the pressure ring method of determining a safe load doesn't work. A comparison of this method with pressure determination with data from lab calibrated strain gage systems showed that there is no, none, nada repeatable correlation between web measurements and pressure. That is to say, sometimes it did give an indication and other times it did not. Such a system is no system at all.

What this leaves us with are the manuals (which have a built in safety margin), our personal observations of many indicators (primer pockets, primer condition, extraction, etc), and velocity which is most easily measured by chronograph.

Regarding a comment by Seafire regarding when one uses the chrono in load development, obviously you cannot start with a velocity measurement because you have to load a cartridge to fire it. The trick is where to start and, more importantly, when to stop!

To you new guys, please note with all our "disagreements" we all are attempting to avoid over loads which are dangerous. We would all tell you to be cautious. You cannot just pour in the powder and go until something breaks. Believe me, I have seen one catastrophic case failure (wrong cartridge in rifle), and it is ugly.

Use all the information and resources at your disposal, and use a chronograph! It provides the most info for the least cost you can get. Kudude

quote:

Originally posted by kudude:
HotCore,

Are you seriously suggesting that there is not a direct correlation between pressure and velocity?

Kudude

I am seriously saying no one can tell what the Pressure is from Velocity.

quote:

Originally posted by kudude:

When we started loading, there was very little knowledge about what actually went one inside the case and barrel when a shot was fired. It was only with the development of strain gages and high speed measuring equipment that data could be obtained on pressure over time in the barrel.

I totally disagree. Perhaps you are simply dating yourself as not being as old as some of us. But, your entire premise that we knew nothing before Strain Gauges is waaaaay wrong.

quote:

Studies using these methods showed that was a peak pressure and an average pressure. It is the peak pressure that one has to worry about.

Actually we have to be concerned about both the Peak, Average Pressure and the Duration of the Burn.

quote:

As the bullet moves down the barrel in increases the volume of the "cylinder" geometrically; therefore, there are one or more pressure peaks reached during a shot. ...

Some folks do believe that based on what is shown on Strain Gauge devices, but it has not been proven that the second Spike actually exists.

quote:

For reasons identified by another poster regarding not only differences in different lots of brass, but the same lot after different firings, the pressure ring method of determining a safe load doesn't work. A comparison of this method with pressure determination with data from lab calibrated strain gage systems showed that there is no, none, nada repeatable correlation between web measurements and pressure. That is to say, sometimes it did give an indication and other times it did not. Such a system is no system at all.

If you are talking about the fool who gave us the World's Most Ignorant Reloading Suggestion, there are very few people with common sense that consider anything he has to offer as worthwhile. In my mind your argument falls apart if you are using him as a source.

The reason I suspect it is the fool, is because anyone else would have determined how repeatably accurate both CHE & PRE happen to be.

quote:

What this leaves us with are the manuals (which have a built in safety margin), our personal observations of many indicators (primer pockets, primer condition, extraction, etc), and velocity which is most easily measured by chronograph.

All the Bullet and Powder Manufacturers used both CHE & PRE for over 100 years, as well as my Elders and the Gun Scribes of the past. The Factories moved to Copper Crusher equipment and then Piezo(which is the absolutely Best) Pressure Detection Devices. However, all the Factory devices were Calibrated to SAAMI Calibration Ammo(Reference Ammo as Dr. Oehler calls it). Nothing was used at the Factories, and nothing is used at the Factories, without proper Calibration to a Known Standard - as it should be.

quote:

To you new guys, please note with all our "disagreements" we all are attempting to avoid over loads which are dangerous. We would all tell you to be cautious. You cannot just pour in the powder and go until something breaks.

Completely agree.

quote:

Believe me, I have seen one catastrophic case failure (wrong cartridge in rifle), and it is ugly.

Had Kudude been using both CHE & PRE this situation would not have happened (as long as it was not a defective Case). That is the great thing about the very best Pressure Detection Methods in existance, when used properly, they prevent just what Kudude went through.

quote:

Use all the information and resources at your disposal, and use a chronograph! It provides the most info for the least cost you can get. Kudude

Chronographs have the three uses that I've already posted, none of which tell you a thing about Pressure. Other than timing Velocities, they are a potentially misleading waste of money.
-----

By the way Kudude, I know alf means well, but all he does is copy information from books. You can see when I asked him a few simple questions about his original post, he was totally unable to explain. There is a huge difference between "transcribing data" and actually understanding what the data means with enough clarity to discuss it.

I support your efforts to keep the Beginners from getting into Pressure Problems and the way to prevent it is of course the time proven, never fail, always reliable, CHE & PRE.

seafire2,


Even though I have read post by folks who start with Max loads and exceed them because “the cases look ok†& “the publishers always build a buffer into the max load for safety†those folks always surprise me.

I have always believed a Crono is critical when working up to the MAX of a published load… but I'm just a overly conservative kinda guy.

And Yes I do understand there is not a 1 to 1 correlation between velocity and pressure… but it is something you can use to gauge where you are in relation to the reference manual…
AND I Still believe if you are exceeding max Velocities… you are most likely exceeding MAX pressure.

Woiw, I never intended for this thread to turn into such a pissing matchacademic debate.....

Kinda reminds me of college....

the bar closes in 5 minutes, there are 5 horny guys and one girl left in the bar....

quote:

Originally posted by seafire2:
Woiw, I never intended for this thread to turn into such a pissing matchacademic debate.....

Kinda reminds me of college....

the bar closes in 5 minutes, there are 5 horny guys and one girl left in the bar....

Seafire2

Anytime Hot Sh$t is involved that's all it can become is a pissing match.

Amazing and pitiful a real danger to beginners like himself, ireload my pants, and montdog.

Most people come to these board to share and learn, he comes to condemn and flame.

Just because my ancestors used the hand crank to start farm tractors, trucks and cars doesn't mean I have to. Something better came along...the 12V electric starter. Did it cost more? You better believe it.

I tried and tried to use a .0001" capable micrometer to measure case head expansion. You can forget about the first three zeros. It is the fourth place to the right of the decimal that provides all the info. Determining whether my case expanded .0004" or .0005" (or something in between) was difficult for me to do. Measuring the same case 2 or 3 times gave 2 or 3 different readings. I found that any info was just too inaccurate to be of use.

So I wrote the big check to Dr. Oehler in '98 for the 43PBL and have no regrets. As instructed by Dr. Oehler, I gage my handloads against factory loaded ammo. I feel safe as long as I don't exceed the pressures generated by Federal, Winchester, Hornady, Nosler, etc.

If we're dropping 'names' from the shooting industry...the likes of Rick Jamison, Dean Grennell, Jon Sundra, Charles Petty, Jim Carmichael, Layne Simpson and Ed Matunas seemed to agree that the 43PBL is as much an improvement over the micrometer as the calculator is over the sliderule.

I get a million times more enjoyment using Dr. Oehler's equipment than trying to fight with any brand of micrometer ever made. Couple that info with the in flight ballistics from the accoustic target and I get lots of data I can store on my computer or print out for future reference.

Hot Core's rants fall on my deaf ears. I think he's living in the past. I commend him for keeping the old ways alive but I decided to move forward.

Here is the thread where Dr. Oehler answered some pointed questions.

And here is one of the exchanges.

quote:

Question to Dr. Oehler:
5. If we consider the "Range" of variance you mentioned, 3%-8% with an average of 5%, if we consider the worst case situation with a HSGS, and if the system indicates 60.0Kpsi, are you saying the actual pressure could vary plus or minus 4.8Kpsi for a "potential Range" of 55.2Kpsi <-> 64.8Kpsi? But for most users who pay close attention to the Set-Up and follow the directions the average variance would typically be(5%) with a Range from 57.0Kpsi <-> 63.0Kpsi?

quote:

Answer from Dr. Oehler:
You've got it! That's much better than thinking you are at 50K and actually be exceeding 75K.

-----------

For all the folks who talk about the MAJOR "modern" advantages and HUGE confidence gained when Developing your Loads due to the "vastly superior Accuracy"( ) of a typical (non-Calibrated) HSGS, are you all saying Dr. Oehler is wrong?

Perhaps alf and tater-tot can explain this HUGE, MASSIVE possible variation in the HSGS readings.

I'd like to register my agreement with Seafire as to when I almost always use my chronograph, and why, even if I don't use it as my primary tool in developing loads for my rifles.

I agree wholeheartedly that is important to know at least the calculated trajectory of your bullets fired from your rifle, even if you don't have a local range where you can measure ACTUAL drop.

There are some other times when velocity is definitely an indicator it is a good time to stop adding powder and perhaps reduce an amount that has shown no signs of excess pressure in your brass.

One time I can think of, I was helping another reloader develop a 1,000-yard benchrest load with a powder which was on the market only a short time, and for which there was no good published data for his cartridge, the .300 Wby Mag. The powder, should anyone care, was TCI-5050, a very small grained spherical powder.

His rifle was a Ruger 77(?!) with a 30-inch barrel. Anyway, we started at the mid-to-high 80 grain range, using one of the bullets which had proved most accurate in that rifle with other powders...the 200 gr. Nosler Partition spitzer (of all things).

We used CHE and gradually worked our way up through 94 grains of powder in half grain increments. Velocities started showing nice, relatively even increases at about 90-91 grains, and continued nicely thereafter up through 94 grains. There were NO CHE signs of excess pressure on any one of the individual cartridge cases. BUT, at about 94.5 grains, velocity barely changed. At 95.0 grains, it actually began to drop. WHOA, I said...it's time to decrease this charge by about 2 grains or more.

There were no signs from case measurements that we were verging on any trouble, let alone serious trouble, but trying not to live as a danged fool, I thought we were, so we decreased the load. After the reduction we were still getting .5 MOA accuracy from the Noslers, and 3,300 fps velocity, so it was time to accept "good enough".

Perhaps that sounds like a complete endorsement of using a chrono as a loading guide. It isn't.
I use CHE as my primary load check because, if measurements using the CHE process had shown even one case to be changing significantly (as often does happen), I would have stopped adding powder and reduced the load even earlier.

I use CHE AND a chrono when loading unknown powders. Whenever either one indicates worriesome new developments, I stop advancing and take a step back.

Don't know if that has ever really saved my bacon, but I would bet it has. I think it would have in the situation with the Krag which I posted about earlier, had I been using both instead of just a chrono.

Whatever, it has been an interesting discussion, with both points of view pretty well covered, I think.

Hot Core,

With regard to your comments to my posts (quoted in brief):

"You are not suggesting there is not a direct correlation between pressure and velocity?"

While one cannot tell an exact pressure from a particular velocity (in a particular cartridge formulation), one can establish trends with regard to a particular rifle and with regard to bullets and powders that when compared with published data give you some idea about where you are.

If your CHE/PRE is .0002 greater than a factory round with a bullet of the same manufacture you are using, what do you know about the absolute pressure? Its relative pressure in comparison? Suppose you want to use a bullet that isn't being loaded commercially (which is why most of us reload or we'd have just bought it off the shelf?)

"When we started there was very little knowledge about what when on inside the barrel..."

You can disagree all you want, but it isn't going to change the fact that until we had instrumentation like strain gages, oscilloscopes and computers (or other means to capture the data at very high speed), we had no way to "look" inside the barrel.

"The peak pressure is the one we have to worry about."

Yes, there is/are average(s) pressure and there are burn rates, but what cause a case failure is peak pressure that is "over the top."

"...there are one or more pressure peaks reached..."

Please refer to the article at www.shootingsoftware.com ; support; PRE, CHE RIP for an interesting article on strain gages v. PRE and CHE. They are trying to sell a product; however, I believe Rick Jamison did a similar work up reported in one of the gun mags using someone's ballistic lab and reached similar results.

"...differences in brass...."

You may ridicule the messenger, but it does not change the content of the report. The referenced article above also addresses the issue of brass differences and their impact on the CHE and PRE methods.

"What this leaves us with ..."

Doctors use to do surgery without anesthesia, but I don't think you would want to have such care. I challenge you to provide a list of current manufacturers and recent articles by date by gun scribes advocating CHE or PRE. (PS: I'll try and find the Rick Jamison article I referenced above too.)

Further, the calibration issue is a red herring because without calibration you will still get relative readings which is all you get with PRE or CHE unless you compare readings against factory loads (see comments on differences in brass above.) With calibration against factory loads, strain gages will give you similarly comparative readings.

"I've seen catastrophic failure..."

Unfortunately my failure was more basic and worse (read more stupid!) than a reloading error; I put a 30-06 round in my 30-338. I discovered the coefficient of expansion of brass will not let the 30-06 fire form in a 30-338 chamber, and that 55000psi will blow lots of parts off a M70. Fortunately, no one was hurt, but trust me on this, YOU DON"T WANT TO BLOW A CASE!

By the way, I hope you are enjoying this as much as I am and I can tell that both of us have too much time on our hands! Gosh, I hope I can go burn some powder soon. Kudude

AC,

I had the reverse happen where rather than having a sharp up turn, the velocity curve stayed straight and all of a sudden we had pressure signs.

Shows that there are no hard and fast rules. You have to pay attention to everything like you were doing. Kudude

Very interesting und schmart too! Vere ist mine helmet? roger

quote:

Perhaps alf and tater-tot can explain this HUGE, MASSIVE possible variation in the HSGS readings.

Glad to help you out of a tight spot, Hot Sh$t.

Just always remember......... you usually wrong. Simple but pitiful.

quote:

Originally posted by kudude:
I make these comments because the posts here are read by many new comers to reloading, and some of the things people posts could lead them to dangerous practices.

As I have said to anyone who posts this idea, since the WWW started up 10 years ago, on any subject*:

quote:

Don't worry, no one is more ignorant than you

*e.g. The idea that a beginning operator of a microwave could choose his own cook times is crazy and dangerous. The proposer of such insanity will cause a house to burn down, resulting in deaths, law suits against this web site, and manslaughter charges against the person I am now flaming. The moderator should promptly delete the posts of, and ban the dangerous nut case I am flaming.

quote:

Originally posted by Alberta Canuck:
...One time I can think of, I was helping another reloader develop a 1,000-yard benchrest load with a powder which was on the market only a short time, and for which there was no good published data for his cartridge, the .300 Wby Mag. The powder, should anyone care, was TCI-5050, a very small grained spherical powder.

... Velocities started showing nice, relatively even increases at about 90-91 grains, and continued nicely thereafter up through 94 grains. There were NO CHE signs of excess pressure on any one of the individual cartridge cases. BUT, at about 94.5 grains, velocity barely changed. At 95.0 grains, it actually began to drop. WHOA, I said...it's time to decrease this charge by about 2 grains or more. ...

The second paragraph describes exactly what I was asking alf about his initial post. That is an excellent use of a Chronograph, but should not be attempted by the Beginners, Rookies, jackfish, alf or tater-tot.

It is important to note that what AC saw was the Pressure becoming "Erratic". That does not necessarily mean they had seen Excessive Pressure, but it was an excellent indication that they "might" within the next few shots. I've seen the same "effect" with the RL - Rifle Powders using PRE in my rifles with published Loads.
-----

Hey Kudude, That link you provided was written by the fool I mentioned. So are you saying you believe he actually knows what he is talking about? Apparently you think so.

If so, how do you explain how he could be so wrong about there being an accurate CUP to PSI formula(that no one in the Industry accepts) and his Great Idea to "Drive Live Primers out of their pocket with a sharp pointed tool and a hammer"?

Granted, he can make a Chart on a computer. But when the Data is Bogus, it dosen't mean much to folks with a modicum of Reloading knowledge and actual first-hand experience.
-----

I can't provide any Links to CHE & PRE in current magazines, because I don't take them. But, I doubt anyone who actually knows how to use CHE & PRE has written an article about it in many years(other than me). Darn shame, because(as we all know ) they are the very best Pressure Detection Methods in existance.

quote:

Originally posted by Hot Core:
Here is the thread where Dr. Oehler answered some pointed questions.

And here is one of the exchanges.

quote:

Question to Dr. Oehler:
5. If we consider the "Range" of variance you mentioned, 3%-8% with an average of 5%, if we consider the worst case situation with a HSGS, and if the system indicates 60.0Kpsi, are you saying the actual pressure could vary plus or minus 4.8Kpsi for a "potential Range" of 55.2Kpsi <-> 64.8Kpsi? But for most users who pay close attention to the Set-Up and follow the directions the average variance would typically be(5%) with a Range from 57.0Kpsi <-> 63.0Kpsi?

quote:

Answer from Dr. Oehler:
You've got it! That's much better than thinking you are at 50K and actually be exceeding 75K.

-----------

For all the folks who talk about the MAJOR "modern" advantages and HUGE confidence gained when Developing your Loads due to the "vastly superior Accuracy"( ) of a typical (non-Calibrated) HSGS, are you all saying Dr. Oehler is wrong?

Perhaps alf and tater-tot can explain this HUGE, MASSIVE possible variation in the HSGS readings.

I must have overlooked the Answer to the above question from you Haphazard Strain Gauge worshipers.

How `bout it? Any of you care to argue that Dr. Oehler is baaaaad wrong - that the HSGSs are not grossly inaccurate???

That makes as much sense as believing anything the fool who made the World's Most Ignorant Reloading Suggestion has ever written concerning Reloading. Pitiful!

Why yes. I have a whole list of very bad advice, posted on this board, that could easily lead beginners astray. Thanks for inviting me to share.

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.

The above post was from another board member and is a little old.

Sorry about the above post. My keyboard batteries went bad during it.

The above post is from another board member and is a little old. Perhaps he has updated it recently as it's been quite a lont itme since that post and I'm sure that the list has grown since then.

It's a good summary of why Hot Sh$t is pitiful and dangerous to himself and his two buddies and other beginners.

quote:

Originally posted by TEANCUM:


..pitiful .. dangerous ..

yeah yeah

I see rifles (and other firearms), to be like women women all have the same reason to exist, they are all the same, yet all different. If you treat them nice and don't push them to hard they can be fun and very useful. If you try to get too much out of them or put too much pressure on them they may explode or cause you some other problems; but once you find the sweet spot nothing can be better.
So; if your trying to get the max out of your firearm be aware that there are limits and that every on is an individule and need to be treated different then another that may look the same, or look better. Some of my best shooting guns are not the prettiest or the newest.
Mike

quote:

Originally posted by Hot Core:
The second paragraph....

It is important to note that what AC saw was the Pressure becoming "Erratic". :

I would like to confirm that this observation is correct. At both 95.0 grains (and 95.5 grains whch I tried later, out of curiosity) the AVERAGE velocities were lower BECAUSE THE VELOCITIES WERE MUCH MORE ERRATIC. Remember, at all of these load levels we were shooting not just one chrono'd shot, but 5 shots. When we got to 94.5 grains, extreme spread for the 5 shots about doubled, but produced about the same average velocity.

At 95.0 grains, the extreme spread for that 5 shots more than doubled, and the average velocity was actually lower. At 95.5 grains, the extreme spread for those 5 shots considerably more than doubled, compared to the extreme spread at 94.0 grains of powder and the resulting average velocity was even lower.

I took those to be VERY bad signs of burn inconsistency, with some individual shots apparently producing markedly high pressures (and velocities) while at other shots the powder apparently did not all burn thoroughly while still in the barrel, and their velocities dropped significantly.

That suggested to me that we were probably beyond the "pressure envelope" in which the powder was intended to burn, and/or we were trying to use too much powder for the expansion ratio/capacity of that chamber & bore. Neither was where I wished us to go.

Cheers, y'all.

Hey tater-tot, You did find a nice old list from the fool I previously mentioned. And in fact, some of it is True.

Would you have any idea which claims are True statements and which are False?

I know you don't have a clue.
-----

Still no response about the "accuracy" of the HSGSs?

/

quote:

Originally posted by ALF:
rookie, low life, no good scum bag

yeah, yeah, yeah