Not a newbie, but still learning. Recently, I again read that when developing loads, to start by selecting two or three powders which give highest velocity and, preferably, yield low, or lowest, pressure.

However, only two of my loading manuals provide pressure: Hodgdon's 2010 Annual Reloading Manual and Lyman's Reloading Handbook, 48th Ed. But, they do not include all powders. Hodgdon appears to show readings just for its propriatary powders: Hodgdon, IMR & Winchester. And, Lyman gives pressure for most of loads but omits some.

My other manuals: Barnes, Nosler, Hornady, & Speer do not provide pressure entries. Wouldn't you know, a couple of powders I was considering did not yield pressure entries.

I understand there are programs (and instruments?) which will provide the info. But, is there a way to calculate pressure, like a formula? Without explaining why, I prefer
not to spend the money for programs or instruments, etc., at least at this point.

If highest velocity is your goal there is a thing called area under the curve. The "curve" is the time pressure curve (plot or graph).

The largest area under the curve without exceeding safe pressures give the highest velocity.

However there are other qualities to consider.
1. Is there a lot of reliable data for the powder in question
2. Is the powder a proven product that will still be on the market and available next year.
3. Muzzle flash and blast
4. Is your powder choice flexible and useful in other cartridges?

Yes there are gross equations for pressure calculation but they cannot possibly account for all the variables that will predict when your case heads will fail.

Olguy,
That's why I finally decided my 5 or 6 books did not provide enought data and broke down and bought one of those fancy programs.

WOW. What did I ever do with out it....

Chamber pressure is measured, not calculated.

quote:

Originally posted by Jim C. <><:
Chamber pressure is measured, not calculated.

Umm, no.

Both copper crusher & piezoelectric methods require the use of formulae to calculate the pressure.

And how many of us have copper crushes and piezoelectric gauges that we can take to the range with us everytime we work up a new load?

I tend to shake my head a bit when I see people obsessing over chamber pressure. If a 5 or even 10% change in pressure is the difference between nirvana and armageddon then you really like to skate on thin ice. Pressure measured in a standard pressure barrel is not the pressure in your rifle. Start low and work up to best accuracy. If you are not getting the velocity you want then try something else. Programs and manuals will get you pretty close, but that is all they need to do.
Just my opinion.
C.G.B.

Who's obsessing? Reread orig. post. Purpose is in selecting best powder. Is knowing pressure, as well as highest velocity, critical in selecting a powder? Not hardly. Would it be helpful? Certainly. And, of course, after selecting a powder you should always start low & work up.

Why is it that some folks on here are so quick to jump to conclusions and inferences and then get hypercritical? Not to mention the sarcasm.

quote:

Start low and work up to best accuracy.

Working out a load is about finding the sweet spot for your rifle, unlike someone who believes to obtain the highest velocity that the gun will stand, as if that extra bit of velocity will do you any good.

Warrior

quote:

Originally posted by olguy:
... is there a way to calculate pressure, like a formula? ...

Yes, but it would drive you to liquor trying to do it by hand.

quote:

Why is it that some folks on here are so quick to jump to conclusions and inferences and then get hypercritical?

Part of the obummer "change"?

quickload has more than paid for itself, for me, in saving bullet, powder, and range time by helping me select correct powders...

and, inversely, its saved me even MORE by letting me work with h335 for most of my centerfire rifles.

EVERY load in a book is under preceived pressure max for THAT rifle used. very few actualyl use pressure barrels, but that is changing.

work up to book max, and work down from there for accuracy.

there's very little USEFUL data to be gleaned from max pressure, other than as a safety margin.

but, remember, EVERY max load in a book, for a caliber and bullet, are loaded to about the same pressure for caliber, except reduced loads. look at a 30-06 180gr .. see the huge spread from whatever to rel22 ... these are all loaded to about the same pressure.

as sr4759 says, WORK (area under the time/pressure (nonlinear) curve is what delivers vel.

and the last 100 FPS is the most 'expensive' in terms of lots of pressure needed per FPS.

Didn't mean to sound quite so sarcastic. What I was trying to say is that if some one has pressure tested a load then that same load in your rifle will probably be close. If you really want to know what the pressure is in YOUR rifle, ie you want to know what the pressure/time curve really looks like down to a gnats ass, then that is a much more difficult problem. Oehler's system ( I haven't used one) might get you close, but in the end rifles make really lousy pressure transducers.
C.G.B.

quote:

Originally posted by Antelope Sniper:
And how many of us have copper crushes and piezoelectric gauges that we can take to the range with us everytime we work up a new load?

So tell me another consistent & accurate way of measuring pressure.
Whatever method chosen requires formulae to produce meaningful pressure readings & TBH I can't think of a reliable & accurate method outside the two I mentioned.
I'm sure that if there were, cartridge manufacturers would be using it instead of the other methods.

I do not have a program for calculating pressure but I was advised to first buy & read the Lyman manual. That was the best advice I got for reloading. The Lyman manual is the only one which gives actual pressure readings for each load - stating & max. The new edition gives PSI and / or CUP readings for some cartridges.

I also learned to do case head expansion measurements. I made up simple wood inserts for each case to be used with the micrometer so that I was measuring all the cases at exactly the same spot.

I usually get 1" accuracy with hunting rifles & sometimes 0.5". Most of my rifles shoot near max velocity and one does just a bit more. I never have to try more than 2 or 3 powders to get my desired results. I find a chronograph the most valuable tool in achieving this.

quote:

EVERY load in a book is under preceived pressure max for THAT rifle used. very few actualyl use pressure barrels, but that is changing.

I'd say it changed a long time ago. Speer began using pressure barrels by 1974, Hornady and Sierra started around the same time. Nosler has used pressure barrels since at least 1989. Hodgdon too has used pressure barrels for many years. They use the SAAMI pressure specs for each tested cartridge to determine the max load, not some "perceived" value.

Actually, the trend seems to be opposite to what the quote above suggests. More and more manuals are using the Oehler pressure stress gauge machines on factory rifles. A lot cheaper than true "pressure barrels" mounted in universal receivers, and if they don't have to report pressure in cup or psi it works fine.


.

Two powders can yield the same velocity from the same barrel and have different peak pressures and pressure curves. You may not like my answer but if you have an appropriate powder, and a good group; what difference does it make if you know the pressure?

quote:

Originally posted by Nakihunter:
...I also learned to do case head expansion measurements. ...

Best answer in the thread. CHE & PRE will tell you what is happening to the actual Case. No other Method or Device can do that.

It doesn't matter what the actual Pressure happens to be once the Case begins deforming. That is when it is time to Stop dumping in more Powder and look back through the Targets for the Harmonic Nodes.

quote:

Originally posted by TX Nimrod:

quote:

EVERY load in a book is under preceived pressure max for THAT rifle used. very few actualyl use pressure barrels, but that is changing.

I'd say it changed a long time ago. Speer began using pressure barrels by 1974, Hornady and Sierra started around the same time. Nosler has used pressure barrels since at least 1989. Hodgdon too has used pressure barrels for many years. They use the SAAMI pressure specs for each tested cartridge to determine the max load, not some "perceived" value.

Actually, the trend seems to be opposite to what the quote above suggests. More and more manuals are using the Oehler pressure stress gauge machines on factory rifles. A lot cheaper than true "pressure barrels" mounted in universal receivers, and if they don't have to report pressure in cup or psi it works fine.


.

It's illegal for a firearms or ammunition manufacturer to use a strain gauge for developing their products and the real is simple.....they aren't nearly accurate enough.

quote:

Originally posted by SmokinJ:

It's illegal for a firearms or ammunition manufacturer to use a strain gauge for developing their products and the real is simple.....they aren't nearly accurate enough.

Do you have a legal reference to that? I've never heard this before.

quote:

Originally posted by jeffeosso:

quote:

Originally posted by SmokinJ:

It's illegal for a firearms or ammunition manufacturer to use a strain gauge for developing their products and the real is simple.....they aren't nearly accurate enough.

Do you have a legal reference to that? I've never heard this before.

I don't have the legal reference per se, but I have been involved in the on going fiasco of Hornady trying to get the 6.5 Grendel SAAMI spec (that's a whole other story) but was told by Hornady that the 6.5 Grendel factory ammo was down right hot if not border line dangerous. That brought up the discussion for the reason which was that it was developed with a strain gauge. Then was told by two leading manufacture that SAAMI won't accept the use of a strain gauge, that they don't use a strain gauge, and that to publish loads developed with a strain gauge can have legal ramifications.

Think about it, very often a strain gauge cannot be placed directly on the chamber portion of a barrel in many firearms. In fact the only ones that come to mind are single shots such as the Thompson Contender models. On other firearms the stress ( or strain) has to penetrate through the barrels and receiver...and often more obstacles such as in the case of the AR15/AR10.

Illegal? Says who? Show me the law Joe, there's numerous companies that use strain gauges (in particular the Oehler machines) in load development. I know of no law that governs what devices are used in ammuntition development.

Strain gauges are every bit as accurate as transducers and some what more so than CUP methods. Dr. Oehler conducted an extesive test (probably the only one to do so) where by he used a single universal receiver for measuring CUP. To that receiver with '06 test barrel he also attached 2 strain gauges (M43/M83), 2 conformal PCB M 117B31 transducers (industry standard transducers) and one case mouth PCB M165A01 transducer (now used by the US Gvn't for NATO ammuntion psi measurements). Thus with each shot the psi was measured by 6 independant methods.

The results gave, what Dr. Oehler refers to, an "equivelence" of measurement. To quote Dr. Oehler; "Conformal, strain gauge, and case mouth measurements yielded results that agree within a few percent, and our original idea of "equivelence" is supported." In other words if you look at the data the 2 strain gauges were every bit as accurate as the conformal and case mouth transducers. Those five also gave a more complete "picture" of psi than the CUP method.

Dr. Oehlers report is quite detaled, as expected, with a lot of data from the 60 test rounds fired. I can email you the test report if you like. It is very lengthy and I don't know if I can post it here. I have Dr. Oehler's permission to post it BTW.

I've now over 2 years experience with the M43, have applied strain gauges to 23 firearms and have conducted a lot of test strings. The correct application and position of the strain gauge is critical. A misplaced gauge, as in the HC .223 tests, can easily give erroneous results. I have had to attach several new gauges until I got the method down correct. I use the SAAMI transducer location (shown on SAAMI's chamber spec's) to place to attach the strain gauge. I also have used "reference" ammuntion to validate (no HC, you do not "calibrate" the machine using "reference" ammunition) the psi readings. I also use one .308W rifle with one lot of ammuntion as "reference" to validate the set up each time the M43 is used.

There is a lot of data input prior to testing and it is far different from setting up a chronograph to use. With proper attachement of the strain gauge and a consistent and proper set up each time I have found the M43 to give very consistent and reliable results. When something is not correct there are numerous indicators and internal "checks" that tell you. Also remember that the psi readings I get are only with the barrels and componants that I use. That is just the same as with the psi data the industry publishes; it applies only to their pressure test guns and componants used. They all say that in the fine print of the data/manuals. That's why the mantra is; "start low and work up" when you develop loads.

The use of a strain gauge to measure psi can be very accurate if the gauge is properly applied, the soft ware correct and the set up is consistent and correct. This is the same as with a transducer; incorrectly attach it, input bad data and don't use a consitent set up and the information attained will be unreliable.

Again, there is no law that governs load or ammuntion development. If there was don't you think the liberals and anti-gunners would apply it to every handloader out there to put them out of reloading ammuntion? Of course they would. There is no "law" and there is nothing "illegal" about the use of strain gauges to develope ammuntion. Many companies use the M83.

Larry Gibson

quote:

It's illegal for a firearms or ammunition manufacturer to use a strain gauge for developing their products and the real is simple.....they aren't nearly accurate enough.

I respectfully disagree:

It is not that strain gauges are not accurate enough, they are very accurate, it is that as far as CIP goes they are not part of, or defined in the various measuring pathways and statistical limits mandated in the protocols.

Big difference !

As for legal status.

The CIP protocols are legally binding entities for those jurisdictions ( countries) who are signatories.

But here lies the problem:

The internal ballistics event is entirely stochastic !

Secondly the physical act of measurement using a device, any device is not absolute ! There is always a degree of error inherent to the method used.

Therefore any measuring pathway whether you are measuring the effect of pressure on the behaviour of brass with a micrometer, the behaviour of the barrel steel to pressure using a strain gauge or measuring pressure using a transducer as in a pressure barrel all raw data has to be subjected to statistical analysis !

I believe Alf said it best. Sure many use the strain gauge to publish loading data but none of the major industires. Nor will SAAMI use it.

Larry, the Anti's going after that is small beans. Unless you haven't been informed Obama is working on passing a bill, behind the scenes, which require ammunition to be shipped by NATO specifications. To make that simple that means all ammunition has to be shipped in NATO container and in a nut shell this will shut the whole industry down.

Back to the strain gauge...it's only as accurate as the person using it properly which can have a much wider variance then the other two methods.

SAAMI is not a law, its an organization... of manfs, actually.. its not CIP.

i don't believe it to be illegal.. and would like to see reference.. the military uses oehler strains./

quote:

Unless you haven't been informed Obama is working on passing a bill, behind the scenes, which require ammunition to be shipped by NATO specifications. To make that simple that means all ammunition has to be shipped in NATO container and in a nut shell this will shut the whole industry down.

Could we get more info on this please. How would it affect us? We need to understand this better, so it can be challenged by the Republican politicians. Doing things behind the scenes is not tranparent as he claimed he would be, nor democratic.

Warrior

Joe

You are really behind times, seems your clock stopped about 20 years ago regarding strain gauge use to measure pressure. Most all of the "major industries" (assuming you mean ammunition manufacturors) do, in fact, use strain gauges on commercial firearms to confirm the pressure data from their universal test fixtures. Many use the Oehler M83 as well as the military uses various Oehler models to measure pressure and velocities, both muzzle and down range. You should do a little more research.

You also need to quit looking for black helicopters. I never said Obama was doing anything. I said there was no such law to make it "illegal" as you erroneously claim. And who mentioned ammo shipped by NATO spec? I was referring to loading ammuntion without the extensive equipment the manufacturers have, including stran gauge M83s, to develop loads with. Look outside, I don't think the FBI or ATF is sneeking up on anyone for loading ammo without pressure testing it, including the manufacturers of ammunition.

Sometimes I worry about you

Larry Gibson

quote:

Originally posted by Warrior:

quote:

Unless you haven't been informed Obama is working on passing a bill, behind the scenes, which require ammunition to be shipped by NATO specifications. To make that simple that means all ammunition has to be shipped in NATO container and in a nut shell this will shut the whole industry down.

Could we get more info on this please. How would it affect us? We need to understand this better, so it can be challenged by the Republican politicians. Doing things behind the scenes is not tranparent as he claimed he would be, nor democratic.

Warrior

Warrior

There is no "more information on this". Joe is smoking something again and halucinationg

Larry Gibson

quote:

Umm, no. Both copper crusher & piezoelectric methods require the use of formulae to calculate the pressure.

Trivial esoteric comments aside, that's irrelivant to the man's question; the pressure first has to be measured. And neither he nor YOU are likely to be doing that.

quote:

Originally posted by Larry Gibson:

quote:

Originally posted by Warrior:

quote:

Unless you haven't been informed Obama is working on passing a bill, behind the scenes, which require ammunition to be shipped by NATO specifications. To make that simple that means all ammunition has to be shipped in NATO container and in a nut shell this will shut the whole industry down.

Could we get more info on this please. How would it affect us? We need to understand this better, so it can be challenged by the Republican politicians. Doing things behind the scenes is not tranparent as he claimed he would be, nor democratic.

Warrior

Warrior

There is no "more information on this". Joe is smoking something again and halucinationg

Larry Gibson

Come on Larry, thing I smoke is the smoke off my gun muzzle blowing back into my face. Here's what I got Larry & Warrior....this is really serious!

Elimination of ORM-D Classification

In an attempt to harmonize and align with international standards, the DOT has amended the 49CFR regulations regarding the ORM-D classification. Effective January 19, 2011, with the publication of the HM-215K final rule, the hazard class of ORM-D is being eliminated.

===========================





I just got word of this. Ammo is currently shipped ORM-D. This NEW DOT change is making US abide by UN standards. I haven’t read in detail, I will tomorrow. But in glancing over it, reading in some areas of the reg that ammo may no long have ORM-D status and will be a 1.4S UN 0012 item (ammo) after DEC 2012 and must be certified by a lab to ensure it meets 1.4S classifications. This lab test in not cheap, I had to do one 458 SOCOM type cartridge to export to Canada….$1200.00 to get one type certified, and you talk about red tape paperwork BS. Not just $1200, but about 30 hours of paper drills. Now DOT/Obama wants us to do the same as UN and rest of the world. In addition to the possible certification, if ammo loses ORM-D status, then it must ship by 1.4S UN 0012 and a $30 per package HazMat charge. Not counting the HazMat certification that more people be go through. I’m HazMat cert, not hard to do, but more paperwork just to ship a box of ammo. AND big DOT fines if you make an error. A follow business guy I know here in Brunswick, shipping a copier toner cartridge to Hawaii. It is a HazMat item and he worked up the paperwork, but got the UN # wrong….DOT fined him $8000.00



This will kill shooting in the US. UN also covers the carry of ammo in Personal vehicles. They will just wait on the road to the range.

please make up your mind which shadow government is controlling this.. NATO is NOT the UN

quote:

Originally posted by SmokinJ:
... which require ammunition to be shipped by NATO specifications. To make that simple that means all ammunition has to be shipped in NATO container and in a nut shell this will shut the whole industry down.

quote:

Originally posted by SmokinJ:
... This NEW DOT change is making US abide by UN standards. I haven’t read in detail, I will tomorrow. ...


UN also covers the carry of ammo in Personal vehicles. They will just wait on the road to the range.

Back to the original question is there a formula for calculating (or estimating) pressure? There must be if the software has an algorithm to produce a pressure figure for a given load.

here's the text in the law SPECIFICALLY stating that they aren't restricting small arms shipping

quote:

For Cartridges, small arms and
Cartridges, power device in the ORM–D
hazard class, we are proposing to also
continue authorizing such articles
indefinitely under the exceptions
provided in § 173.63 of the HMR for
domestic transportation by highway or
rail.

just exactly as ORM-D, with less paperwork

http://edocket.access.gpo.gov/2010/pdf/2010-19952.pdf

please do READ the actual law .. "consumer commodities" is defined exactly as ORMD for ammo.

quote:

Originally posted by jeffeosso:
here's the text in the law SPECIFICALLY stating that they aren't restricting small arms shipping

quote:

For Cartridges, small arms and
Cartridges, power device in the ORM–D
hazard class, we are proposing to also
continue authorizing such articles
indefinitely under the exceptions
provided in § 173.63 of the HMR for
domestic transportation by highway or
rail.

just exactly as ORM-D, with less paperwork

http://edocket.access.gpo.gov/2010/pdf/2010-19952.pdf

please do READ the actual law .. "consumer commodities" is defined exactly as ORMD for ammo.

Yes I read it, but you know NATO has a history of not liking out 2nd Amendment and they want to disarm us. Don't think for one second that if you let them have the ball they aren't going to try run for a touchdown. Reading the law they make it sound good, dropping the Haz fee. Ummmhmmmmm...wait see what they do.

I hope you don't buy into taking lead out of bullets really helps the enviroment and animals...do you?

The anti gunners aren't stupid. They don't just come straight out anymore with "We want you firearms". They go about devious ways..such as banning lead, one of the most suitable metals for bullets. They even do that nonchalantly like banning lead in various way such as no more lead wheel weights. They say they fly off the wheel and decompose and get in the ground water. Unhuh, set a piece of lead outside and see what it really does. Oxidizes with the white coating and stays that way for a mighty long time. It's all bullshit. Now don't get me wrong, I don't believe in deliberately polluting and I do think we should recycle stuff as resources aren't forever.

We'll have to wait see what this law change does, but I really can't see the government making things easier for us gun owners.

NATO has no history of any position on the american constitution, in fact, they sell surplus bullets!!! the UN, however, does,...

north american treaty organization - a MILITARY pact

the UNITED NATIONS - a political pact ...

and the change to ORMD is related to the UN shipping.

and don't bring up eco-friendly bullets.. you are already far enough off base that i ain't going to bother learnin you on another subject.

quote:

Originally posted by jeffeosso:
NATO has no history of any position on the american constitution, in fact, they sell surplus bullets!!! the UN, however, does,...

north american treaty organization - a MILITARY pact

the UNITED NATIONS - a political pact ...

and the change to ORMD is related to the UN shipping.

and don't bring up eco-friendly bullets.. you are already far enough off base that i ain't going to bother learnin you on another subject.

Jeff, sorry, I meant UN where I mentioned NATO. I am aware of the difference between the two, but I keep calling both of them NATO. Sorry.

You are wrong on the lead bullets though. Long ago "they" said that lead shotgun pellets were poisoning ducks and geese. "They" said that the University of Pittsburgh,or was it Penn State, done a study on that and is where they got the information. Years later the university said they never done any such study. All fabricated stuff.

A wheel weight will lay along the road for eternity..it's all BS.

quote:

Warrior

There is no "more information on this". Joe is smoking something again and halucinationg

Larry Gibson

You funny guy GI, too funny!

I had a brain fart Scot Scot does that GI stand for Gibson Issue?????

quote:

Originally posted by SmokinJ:
I had a brain fart Scot Scot does that GI stand for Gibson Issue?????

GI-Gastro-Intestinal

quote:

Originally posted by swheeler:

quote:

Originally posted by SmokinJ:
I had a brain fart Scot Scot does that GI stand for Gibson Issue?????

GI-Gastro-Intestinal

I resemble that

Larry Gibson