http://www.jamescalhoon.com/primers_and_pressure.php

Thought this satisfied many of my unanswered questions re. primers. r in s.

I measure the extractor groove expansion, and it seems to be a good indicator for primer pocket expansion, which is the real limit of tolerable pressure.

Measuring the primer pockets themselves with pin gauges is less convenient, and no better in .001" increments as the whole range is .0015"

quote:

SAAMI specifications on primers and primer pockets per "Sinclair International's Precision Reloading & Shooting Handbook" 10th edition 1999

......................Depth min max diameter min max
small rifle primer pocket .117 .123 .1730 .1745
small pistol primer pocket .117 .123 .1730 .1745
Large rifle primer pocket .125 .132 .2085 .2100
Large pistol primer pocket .117 .123 .2085 .2100

.......................Height min max Diameter min max
Small rifle primers .115 .125 .1745 .1765
small pistol primers .115 .125 .1745 .1765
large rifle primers .123 .133 .2105 .2130
large pistol primers .115 .125 .2100 .2120"

Casull and Ketchum have both made cartridge with steel base and brass bodies. These cartridges can go to much higher pressures before the primer falls out.

This method could lead to DANGEROUS assumptions...

I agree.

Gustavo and Nitroman,

There are hand loading forums more amenable to following recipes in load books than AR.

There are perhaps 100 other on line forum more appropriate for beginners.

This forum seems to presuppose a level of being able to read the brass for pressure signs and knowing which guns can be taken to that point.

quote:

Originally posted by tnekkcc:
Casull and Ketchum have both made cartridge with steel base and brass bodies. These cartridges can go to much higher pressures before the primer falls out.

This is like putting a 60AMP fuse in a circuit that is only wired for 20 AMPS.The same with the all the steel cases. I've always appreciated the security from info supplied by the brass when exercised at upper pressure levels. roger

I have been shooting/reloading for quite a few years,(since 1970) and in my un-scientific experiences, my pressure indicators in my rifles have been flattened or flowing primers, until recently, when I aquired my first "Wildcat", a .257 AI on a 98 Mauser Action. Going "By The Book", I have been experiencing near case separation, along with blown primers. The rim diameters on cases with blown primers were .010"-.012" larger, couldn't even get them into a shell holder. I am not a "Hotter is Better" kind of guy, never have been. I will also say that these loads were chronographed, and were under the listed velocities in the reloading manual. I was also getting collapsed cases on some of these rounds. I would say I had maybe a 40% failure rate on these cases, during and after fire-forming. Experiments continue. As an aside, the primers in these rounds were not flattened or pierced, but some primer pockets did enlarge.

quote:

Originally posted by ray in seattle:
http://www.jamescalhoon.com/primers_and_pressure.php

Thought this satisfied many of my unanswered questions re. primers. r in s.

tnekkcc,

Take a look here and read the article. Is good reading if you are inclined to deal with scientific explanations.

http://www.shootingsoftware.com/tech.htm

PRE, CHE, RIP
For those who still think case head expansion is an indicator of pressures....read this and RIP.

Roger,
I don't know use fuses, but I have my personal de rating system for transistors:
10% of rated current
105% of rated Voltage

What does it all mean?
After you blow up enough stuff, you may see a pattern.


Gustavo,
That is by Denton,
He got out argued on this forum on this topic by Hot Core, but would never admit it.
He just could not laugh at himself.

I offer the following joke:

quote:

Why are Baptists not allowed to make love standing up?
Because it looks too much like they are dancing.

What does it all mean?


A person who is afraid of the primer falling out because that would be too much pressure instead of being afraid of pressure because that might make the primer fall out, has a problem thinking.

Hot Core knows how to work up a load, and he would get that joke.
Not too sure about Denton.

quote:

Originally posted by tnekkcc:
Roger,
I don't know use fuses, but I have my personal de rating system for transistors:
10% of rated current
105% of rated Voltage

What does it all mean?
After you blow up enough stuff, you may see a pattern.

Tell you what old buddy, you blow up enough stuff using steel cases and I'm sure you'll see a pattern. roger

Roger I have blown up so many guns on purpose, that I have definitely lost count.

I bought a C96 Mauser to overload it, but the primer pierce. I have steel case ammo with Berdan primers, and I may finally complete the experiment.

I will PM details.

quote:

Originally posted by Gustavo:
...PRE, CHE, RIP
For those who still think case head expansion is an indicator of pressures....read this and RIP.

Hey Gus, That is pretty funny.

Would the "author" of that bologna happen to be the same fool who honored this site with "The World's Most Ignorant Reloading Suggestion"?

Yes indeed a REAL Reloading Genius and Scientific Whizzzzzzz.....

quote:

Originally posted by tnekkcc:
... I have steel case ammo ...

Hey Tnekkcc, Somewhere on this Board, within the past couple of years, there was a guy trying to sell(or maybe buy ) some of the old "Steel Head O'Conner(?)" Cases. I don't remember if he was discussing them in 30-06 or what the size was.

Anyone that is familiar with this design, feel free to jump in and correct me on this. I seem to remember the forward portion was Brass and it screwed onto the Steel Head Portion. The design required thick walls which in turn limited Powder capacity. And they were relatively expensive.

Been way too long ago for my memory.

I have only seen the ones that Randy Ketchum made and the ones 5 years ago on Casull's web site.

Randy's were beautiful male threads on the case head and tapped threads into the cut off brass case.

Randy never went to college, but he is as bright as any engineer I work with. He made a supercharger from scratch and zillions of wildcats. He sells 50BMGs and 20mm he builds.
He is the one that figured out the threshold of supersonic gas in 22" vs 24" rifles shooting CB longs.
And I put that problem in front of the professors

quote:

Why are Baptists not allowed to make love standing up?
Because it looks too much like they are dancing.

I can remember the preacher pointing his finger out in the congregation and saying, "And you shouldn't be hanging around a Pool Hall. Blah, blah, dancing... Blah, blah carousing...

However it was OK to go Bowling.

The Youth Ministry took the teens to a new Bowling Alley for a night out and what should I find in the center of the place - lots of pool tables!!!
---

I sure hope Gus didn't blow himself up following his "hero's advice" on how to remove a Live Primer.

I know an old guy who's mother was obsessed with Christianity.
She kept telling him, "You will dance your way straight to hell!"

He was too shy to ask girls to dance until he had been drinking.

I went to the same church and the speal they gave us was, "It is an excuse to hug a girl and could lead to sex."

Anyway, he turned into and alcoholic and got into wife swapping.

What does it all mean?
When you follow procedures instead of thinking your way through a problem, it saves time and requires less qualified individuals, but sometimes causes silly things to happen. Like fear of dancing instead of fornication or fearing exceeding SAAMI pressures instead of primers falling out.

Think of it as the quantization error of over reaching rules.



Al Gore, replacing science with fear and ignorance, a tried and true method.

Denton didn't get out argued, he got out-shouted.

There's an important difference.

Anyway, there are any number of other experimenters who have tested various "brass" pressure reading "methods". John Barnsness and Dr. Ken Oehler come to mind. The conclusion is all the same: "reading" brass by whatever method is unable to detect pressures in any sort of predictable fashion.

Hot Core, however, is not to be deterred by experiments.

Which reminds me of a saying of a collegue: it's not what you don't know, but what you THINK you know, and don't, that'll kill you".

One of these days, someone is going to follow Hot Core's advise, and kill himself, but I doubt that will deter Hot Core any more than facts..... JMO, Dutch.

If you think that measuring pressure with the brass is too inaccurate, when the pressure limit is the brass, then you can't think well, will get out argued, out shouted, out everything, because you don't know why you are doing what you are doing. Hot Core does the public service of keeping fools from running the asylum.

Those who can't think and spout like and expert need to be challenged.
I admire the good work Hot Core has done in pointing out the self inflated buffoonery, that lacks logic.

The internet is mostly regurgitating simple folk, but AR has some contributors left with some brains.

If you are full of BS, Hot Core is going to point it out.

Those that think that psi is not only the benchmark of beginning of learning to handload, but the benchmark of highest level one can attain as a handloader, are living in denial.

Denton never had the ability to admit to Hot Core than he was wrong. He was just stuck and stubborn.


Al Gore is fighting science with fear and superstition.

quote:

Originally posted by Dutch:
The conclusion is all the same: "reading" brass by whatever method is unable to detect pressures in any sort of predictable fashion.

Well I don't need an expert to tell me that if a case is hard to extract, hard to rechamber,
ejector mark on base, primer crated etc. the pressure is too high.

Conversly if it looks ok and fits back in the chamber it's hardly an overload.
The chamber is the measuring device, along with any other obvious signs.

Eg the last load I worked up the manual said max of 73.5gr. That looked ok so I tried one at 74. That looked reasonable but the case was tight to rechamber. My rifle agreed with the manual exactly.
I don't need to know the pressure reading.

quote:

Originally posted by Dutch:
...Anyway, there are any number of other experimenters who have tested various "brass" pressure reading "methods". John Barnsness and Dr. Ken Oehler come to mind. The conclusion is all the same: "reading" brass by whatever method is unable to detect pressures in any sort of predictable fashion.

Then I'd offer that they are simply doing it incorrectly. Ken Waters and Bob Hagel never had a single problem with CHE/PRE and recommended it as a normal portion of their very astute articles.

Amazing that CHE/PRE has worked very well for hundreds of thousands of Reloaders for well over 100 years (and if we believe Dutch) neither John Barnsness nor Dr. Ken Oehler can figure out how to use it.

quote:

Hot Core, however, is not to be deterred by experiments.

It really depends on "who" is doing them and if they are doing the Testing properly.

quote:

...One of these days, someone is going to follow Hot Core's advise, and kill himself, but I doubt that will deter Hot Core any more than facts..... JMO, Dutch.

I could be wrong, but I believe Dutch has mentioned something similar before. Can't remember my response the last time, but I do want to say that I "partially AGREE" with Dutch - there are indeed some people who should not use the very best Pressure Detection Methods available to the average Reloader.
---

For those of you who are interested, it is fairly easy to determine who would benefit from using CHE/PRE and who shouldn't even consider using CHE/PRE.

Read anything concerning Reloading, Statistics or the "Haphazard Strain Gauge Systems" that was written by denton. If you believe denton is Full-of-Beans, as is show within this thread where Dr. Ken Oehler verifies that the denton psi to cup conversion is nothing but bologna then, using CHE/PRE will work well for you.

If on the other hand you believe ANYTHING denton spews forth(as Dutch does), then CHE/PRE is not something you should consider using. In addition, these same folks should not use or come in contact with many items which would pose serious dangers to them such as:
1. A table spoon.
2. Q-Tips.
3. A tie wrap.
4. Plastic grocery bags.
5. Electric outlets.
6. Any motor which uses fossil fuel.
And for absolutely positively sure
7. Any mechanical device with "one" or more moving parts.



Best of luck to all you folks.

Hot Core,

You forgot the part where Dr. Oehler told you that measuring brass doesn't tell you anything other than the changes in the brass size.

I hope you're not going to be responsible for getting someone hurt today. Sometimes luck is more important than skill. FWIW, Dutch.

quote:

Originally posted by Dutch:
Hot Core,

You forgot the part where Dr. Oehler told you that measuring brass doesn't tell you anything other than the changes in the brass size.

I hope you're not going to be responsible for getting someone hurt today. Sometimes luck is more important than skill. FWIW, Dutch.

True, and brass makes are different. A load that's too hot with one brand may be fine with another. A friend in CO (instructor at the gunsmithing school) used to work up loads with Remington brass til the primers blew out, then switched to Win brass, and that was his elk load. I wouldn't recommend it, but he never had a problem.
I guess I'm old fashioned, but I still use primers as a primary indicator. I've measured cases and had no expansion, but still began to show signs of pressure in the primers (flattening, flowing) and backed off. I think the primer is still the weak link in the chain, even though there are variations in hardness, according to the "experts". Measurements are fine, but there are other things to look at as well; some of which are mentioned in this thread.
Some of the "experts", here & elsewhere, remind me of my old professor. He was often wrong, but, seldom in doubt .

Measuring psi, not for the commercial sale of ammo, but for a specific personal strong rifle, is the folly of fools.

It is like measuring yourself with tape to see if the pants will fit instead of trying the pants on.

Oehler sells tape measures [figuratively].
If you want to buy mail order pants, you need a tape measure.
If you want to see if your pants still fit, you try them on.
Trying on your pants is like checking brass for primer pocket looseness.

If you have the pants, if you have the gun, try it out.

If you as so dumb, that you think psi counts for spit in your own rifle, then your mom should still be buying your pants and sending them to you, and you should be loading to SAAMI pressures, not the limit of the brass case head.

I hope no stupid people are making up their own loads or buying their own pants.

How stupid is someone who can operate a tape measure and he thinks his one process is the best and the only way to fit a man's pants?
He might have an extremely high measurable IQ, like Denton, just wrong and stubborn on one issue.

Those situations require Hot Core to the rescue





Should this kid get a tape measure [read Oehler] to see if his pants fit?





Al Gore, what an idiot!

quote:

Originally posted by Dutch:
...You forgot the part where Dr. Oehler told you that measuring brass doesn't tell you anything other than the changes in the brass size.

Nope didn't forget at all. In fact I "AGREE" that the "Changes in the brass(Cases actually)" is what a person should be directly interested in. Not some unreliable trash provided third-hand by a non-calibrated Haphazard Strane Gauge System.

CHE/PRE shows the easily measurable, repeatable and highly accurate Effects of the Pressure - unlike the Haphazard Strain Gauge Systems which might be off by as much as 8,000psi - according to Dr. Oehler.

quote:

I hope you're not going to be responsible for getting someone hurt today. ...

Hopefully if I can persuade a few more folks that denton(and his followers) are all mentally incompetent, I will surely prevent some folks from getting hurt due to dentonites pathetic posts and skewed data.
---

For the Rookies and Beginners reading along, the Method Greg is Championing has the potential to get you in a nasty Over-Pressure condition prior to the Primer ever showing any effects. This is a multifaceted issue and not simply due to the Hardness of the Primer Cup.

quote:

Originally posted by Greg:
...Measurements are fine, but there are other things to look at as well; ...

Absolutely correct. Use EVERY Pressure Detection Method available, not just one or two. Quite often one will indicate a problem before the others come to your attention. Change cartridges, or components in the same cartridge, and a totally different Pressure Indicator may alert you.

Basically use EVERY Pressure Detection Method available to you - and ignore denton and the dentonites in order to remain SAFE.
---

A noncalibrated Haphazard Strain Gauge System = Reloaders Pyrite (aka Fool's Gold).

quote:

Originally posted by Hot Core:


For the Rookies and Beginners reading along, the Method Greg is Championing has the potential to get you in a nasty Over-Pressure condition prior to the Primer ever showing any effects. This is a multifaceted issue and not simply due to the Hardness of the Primer Cup.

quote:

Originally posted by Greg:
...Measurements are fine, but there are other things to look at as well; ...

Absolutely correct. Use EVERY Pressure Detection Method available, not just one or two. Quite often one will indicate a problem before the others come to your attention. Change cartridges, or components in the same cartridge, and a totally different Pressure Indicator may alert you.

Basically use EVERY Pressure Detection Method available to you - and ignore denton and the dentonites in order to remain SAFE.
---

A noncalibrated Haphazard Strain Gauge System = Reloaders Pyrite (aka Fool's Gold).

I've always found the primers to show signs of pressure way before the case did. I don't always measure them, but usually did after seeing pressure signs in the primers. I have a dial indicator mic that measures to .00005. I'm not saying it doesn't happen, but in 40 years of handloading, it's never happened to me.

quote:

Originally posted by brayhaven:
...I've always found the primers to show signs of pressure way before the case did. I don't always measure them, but usually did after seeing pressure signs in the primers. I have a dial indicator mic that measures to .00005. I'm not saying it doesn't happen, but in 40 years of handloading, it's never happened to me.

Hey Greg, Your 40 years of experience allows you to pick up on subtle changes that the Beginners/Rookies would miss or perhaps notice but misunderstand.

If there was a precise way to compare the visual appearance of Spent Primers, I'd be Championing the Method too. Too many variables for a Beginner to fully grasp with only a few years of Reloading to understand. As you know, even the Firing Pin can alter the appearance of the Spent Primer enough to make describing how it looks in an Over-Pressure condition very difficult. And by the time a Rookie would notice it, he would be way beyond where he needs to be.

That doesn't mean they should not be looking at the Primers though. Just looking at enough of them, over a long time period(like your 40 years), will indeed help detect Pressure.

Best of luck to you.