Pressure Testing in Load Manuals

15 August 2003, 09:47

B17G

Based on some input from several other people that "criticized" some load info I did pass on, by citing information on the load being unsafe based on " it must have too high of pressure".

Their point of reference were some load manuals commonly available to everyone.

So with a little time to spare, I looked up some 800 numbers and called a batch of these companies and asked them about how they test for pressure. I was really surprised at their answers.

I am talking some of the major bullet manufacturers etc, not some side company. What I was told was that, they did not have pressure testing equipment. What they use is calipers to measure the expansion of the case after firing, and 'scientifically" ( their words not mine) estimate what is considered maximum pressure.

No one was really interested in committing to anymore information than that!

So for the book crowd, instead of those that have worked up a load, before they comment on it; I thought this was interesting information to pass on.

I won't mention the five companies I called up, as I will leave it up to others to contact them on their own. That way, any information that they receive will in no way be influenced by the information that I received.

As for me, My conclusion is taken from the sign off for Paul Harvey...." Now you know the rest of the story". [Razz]

15 August 2003, 17:07

Wstrnhuntr

Speer # 9, page 396. The remarks under the little picture read "Measuring a copper crusher to determine presure".

Ive noticed that a lot of their data is still the same as it was then. If P.O. Ackley had pressure testing equipment in his garage then I would certianly hope that an empire like Nosler or Winchester would be able to scrounge up a few bucks for something more than a micrometer to assure themselves that they werent inviting saftey lawsuits and dead customers. [Roll Eyes]

And SAAMI isnt just a little black dude that used to tapdance real good. [Big Grin]

[ 08-15-2003, 08:11: Message edited by: Wstrnhuntr ]

15 August 2003, 19:13

B17G

Western Hunter:
Good points and you would think so huh?
I am sure they want to be in good standing with SAAMI but I questioned after talking with some if they even really take the time, to set it up and record it.

I often wonder if Load Manuals are a necessary evil of doing business, so they put them together every so often. They just dread the expense, and do what they have too.

Many list what they call safe loads, but do not list any pressure numbers. Don't see them listed In Nosler, Speer, Sierra or Hornady manuals at all. Lyman does but not all of them.
Hodgdon does, but not with each cartridge combo.

Just thought it was interesting! [Razz]

19 August 2003, 03:28

Clark

Someone just posted somewhere a link to a place that will test your cartriges for pressure for $5 per cartridge.

I was once critisized for may strength analysis of a 45/70 handi rifle, so I validated it with a test that worked up loads until the brass flowed. I was still critisized. There is a big fraction of the people out there who are not going to be satisfied with anything you do.

20 August 2003, 01:45

John Frazer

Most of these companies come out with new manuals every 5 years or so -- I don't think they have the time to re-shoot every load in that time. Nosler #5 for instance had NO changes from #4 in any of the loads I shoot.

But from everything I've read the companies are pressure-testing their new data.

Speer #13 mentions a couple of times where they completely re-shot the data for a cartridge -- such as the .280 Rem. which now has higher pressure loads.

I recall a Ken Waters article that mentioned some company reducing a load -- they showed it as max but got many complaints from readers including Ken, so they re-shot it and dropped it a couple grains.

The new Sierra manual has a couple changes but I couldn't point you to 'em if my life depended on it.

20 August 2003, 14:50

Magnum Mike

quote:
Originally posted by Clark:
I was once critisized for may strength analysis of a 45/70 handi rifle, so I validated it with a test that worked up loads until the brass flowed.

What were your findings??

20 August 2003, 15:51

Rob1SG

I was re-reading the Aug. 1996 Handloader Mag. they had a article on the 7mm RM and pressure rated loads.The starting load for RL 22 is higher than most reloading books MAX loads. They hooked up a pressure guage and the second load above their start load is 49,100 cup or 60,000 psi. Now if this load is above MAX in todays books what does that tell us.Even taking into account the different pressures in different barrels there seems to be a lot of room.

21 August 2003, 00:37

John Frazer

BTW those interested might go back and read John Barsness's piece in Handloader #209 on "How to Read Loading Manuals."

He says ALL of the companies now use pressure testing equipment and that the reason some don't list pressure numbers is that it would just encourage those who would make assumptions about how far they can go beyond the maximum load. Good point, I can hear the wheels turning: "Hmmm, SAAMI max. for this cartridge is 55,000 psi, and this manual's maximum load is only 54,927 psi -- I'm sure I can get another couple grains in here ..."

John

21 August 2003, 03:58

Clark

MSS,
I got a handi rifle and wondered how much it could take, so being an engineer, I went about a stress analysis. I determined that it was stronger than the brass to my satisfaction and submitted to rec.guns. There an ME proffessor gave me some help. I also got some help from the desinger of the M107, M110, and M158 guns. I then shot some trapdoor starting loads, and got kicked so hard I didn't shoot again for a year.

Then I adressed this question on the Marlin/Nef website forum, and someone said that my analysis meant nothing because I was not qualified. So I did a test work up to validate my calculation.

The chalanger was still not convinced with my test data, and the lesson is more something to do with human nature than guns.

Here is my test data:
45/70 work up with; 405 gr cast with lube bands, CCI 200 primers, Win
brass, old Unique [dirty] powder, chamber well lubricated between
firings with CLP for max bolt thrust.

Quickload calculation of pressure and velocity with 405 gr, Unique

shot 0) 15 gr, 24,700 psi, 1271 fps, no shot fired, listed for Quickload reference point only
shot 1) 18 gr, 33,217psi, 1403 fps, primer looks fine.
shot 2) 20 gr, 39,435 psi, 1485 fps, primer is fine
shot 3) 22 gr, 46,133 psi, 1563 fps, primer looks flat.
shot 4) 24 gr, 53,334 psi, 1637 fps, primer is flat.
shot 5) 26 gr, 61,067 psi, 1709 fps, primer is top hat and flowing,
action popped open and case ejected on firing
shot 6) 28 gr, 69,366 psi, 1778 fps, primer is top hat and flowing, case
head expansion .001", action popped open and case ejected on firing
shot 7) 30 gr, 78275 psi, 1846 fsp, case head expansion .0015" action
popped open and case ejected on firing, some leading in the muzzle.
shot 8) 32 gr, 87,841 psi, 1911 fps, case head expansion .0025", case head separating where case head is flowing into the extractor, action popped open, some leading in the muzzle, and case ejected on firing, primer is spreading out .010"

There was no change in headspace, but I had to stop the work up because of case head separation where the case head flowed into the extractor.

Reference loads:

1) "Loads for the 45/70" from the H.P.White laboratory via "American
Rifleman" 1950~1968 via "NRA Handloader's Guide" 1969 says:
405 gr Rem S.P., 17.5 gr Unique, 1286 fps, 25,240 pounds pressure, for 1886 Win

2) "Lyman's 47th" 1992 says:
400 gr cast, 16.5 gr Unique, 1286 fps, 27,000 cup, for 1886 Win

3) "Lyman's 47th" 1992 says:
385 cast gr cast, 17.5 gr Unique, 1411 fps, 38,500 cup, for Ruger #1

Left to right: unfired, shot 8), shot 7), etc

Rob,
I have overloaded to see what happens in .223, .243, 25acp, 257 Roberts AI, 32acp, 32sw, 32S&WLong, 32-20, 7.62x25mm, 7.62x54R, 8x57mm, 9x19mm, 9x23mm, 357 Sig, 38 sp, 357 mag, 38sw, 40sw, 10mm, 10.4mm, 45acp, 45Colt, 452/70, .410, and 45/70.

In general what I have found:
1) Rimless cases start to fail at 65 kpsi
2) Rimmed cases start to fail at 85 kpsi
3) Rifle primers may be needed to see the brass fail
4) Bullet pinch will cause pressure spikes
5) The cylinder splits and the the top strap breaks on revolvers
6) Old Iver Johnson break top revolvers stretch thier latches
7) CZ52 pistols split the thin bottoms of their chambers
8) The feed ramp intrusion into the chamber support is often the limit in overloading semi auto pistols.

John,
I have written "How to Write a Load Book"

1) Get all the free load data from powder manufacturers; Alliant,
Accurate Arms, Hodgdon, IMR, Vihtavuori, and Winchester.
Ignore Norma, Nobel, Rex, Scot, and Ramshot.

2) Buy the load manuals from the Powder manufacturers that sell them;
Accurate Arms, Hodgdon, and Vihtavuori.

3) Buy the load manuals from the Bullet manufacturers that sell them;
Speer, Sierra, Hornady, Lyman, and Nosler.
Ignore Barnes, Swift, A-Square, and Lapua.

4) Load development:
You need safety margin. If you don't know what that is, put some popcorn
in the microwave for one hour. The instructions on the bag say 12
minutes, and smoke stinks up the lunchroom in 20 minutes. It stinks up
the whole building in 30 minutes. That 20 - 12 = 8 minutes is safety
margin.

5) Writing the loads part of the book:
Reduce the powder manufacturer's max load by 5%. That is your max load.
Reduce your max load by 10%. That is your starting load. Paraphrase any
anecdotes about the caliber written in the bullet manufacturer's load
books.

6) Calibrating test equipment:
The only thing that counts is a calibration sticker. To make one, on a
piece of paper, write, "Popcorn: minimum 10.3 minutes, not to exceed
11.4 minutes". Tape that paper to the front of the microwave. Your
equipment is now calibrated.

7) The other stuff in the book:
Find someone who handloads and take pictures of his hands while he loads
a cartridge.
Paraphrase the pages of text in the load books you bought; accuracy,
safety, blah, blah, blah...

8) Try to do a good job:
With $200 outlay and an afternoon's work you can sell 10,000 books at
$10 each wholesale and $3 each to have printed, you will make enough
money to pay the rent for a year.

HOW TO REVISE YOUR LOAD BOOK.
1) Wait at least a year, or until the first printing has sold, whichever
comes last.
2) Get the latest free load data from the powder manufacturers.
3) Look for any new powders or calibers that were not in your first
edition.
4) To add these new loads, reduce the loads by 5% for max load, and that
by 10% for starting loads.
5) Charge $12 wholesale per book. Make the money last until you write
the 3rd edition.

Cross marketing:
Find some guy who makes benchrest bullets in his garage and get drunk
with him. Fix him up with your sister. If you could start selling his
bullets by featuring them in your book, you would both benefit. You
could find some surplus "blems" to fill in the product line, and he and
your sister may spawn a gun culture dynasty.

[ 08-20-2003, 19:01: Message edited by: Clark ]

21 August 2003, 11:29

Rob1SG

Clark,
I load 72 gr. H1000 under 160 Nosler Part. in my Ruger M77 tang for 2913 FPS. The Hodgdon book says 70 gr is Max at 2905 fps,Speer says 69 gr.for 2936.Nosler does not list a load for that powder. I get absolutly no signs of excess pressure. I use my Chrono/Rifle to tell me what is Max.I never start there I'm always at starting loads and work up slowly.By the way the article states H1000- 73.8 gr for 65,000 PSI his words not mine but it matches my findings.Each rifle is different and must be worked up to max.

22 August 2003, 00:52

John Frazer

Clark,

Your "How To" was amusing but I'm not sure how it responded to anything I was saying.

John

22 August 2003, 01:06

<eldeguello>

Interesting! I have no idea how many of the bullet makers have pressure-test equipment. But one little fact I found real fascinating is that ol' Rocky Gibbs had a pressure gun that he used to test his data for the Gibbs series of wildcats based on the blown-out .30.'06 case!! And here all these years people have been claiming that the published internal and external ballistics of his cartridges "were highly inflated"!! In actuality, he knew both the pressures of his cartridges, and the muzzle velocities as well, because his rounds were chronographed at the Speer facility near his home in Idaho!!

(The loading data for this lineup that was published by Ackley was not tested by Ackley. P.O. merely reprinted some of the things Rocky had printed earlier.)

I notice that there are now some "new" wildcats in existence that look suspiciously like the Gibbs cartridges, in that they are made from .30/'06 cases with reduced body taper, shoulders moved forward, and necks in the .25" range! But they have someone else's initials attached to the names! Gimme a break!!

22 August 2003, 03:51

snowbound

Clark---when you lit that NEF SB2 45-70 off at 87,000 psi, how was the accuracy?? Looks like a good hunting load.

22 August 2003, 04:15

Clark

Rob,
With strong guns, like your Ruger, I increase the charge until the bolt gets sticky, then back off 6% and that is the max load.

John,
I was responding to
QUOTE] BTW those interested might go back and read John Barsness's piece in Handloader #209 on "How to Read Loading Manuals."[/QUOTE]

with my "How to Write a Load Book"

Snowbound,
assuming you are serious...
My handi rifle kicks to hard with Trapdoor loads. Those shots were fired with my left hand's fingers on the butt and my right hand pulling the trigger. The last two shots had terrible leading with 405 gr hard cast with one lube ring. I only used Unique to get the pressure up. You want to hunt with a gun that pops open and the brass is flowing into the extractor?

[ 08-21-2003, 19:15: Message edited by: Clark ]

22 August 2003, 06:04

snowbound

Clark--I load to Level 2 with IMR4227, IMR 3031, or Various Hogdgon Powders..405 R-P JFP---if you have to penetrate something make it hard, slow and deep---45-70 NEF SB-2--When the game is in the crosshair, re-coil becomes only a relative matter..

22 August 2003, 07:14

John Frazer

quote:
Originally posted by Clark:
John,
I was responding to
QUOTE] BTW those interested might go back and read John Barsness's piece in Handloader #209 on "How to Read Loading Manuals."

with my "How to Write a Load Book"

[/QUOTE]

Clark,

I got the reference but wasn't sure if you were suggesting this is how loading manuals actually are written ... I can think of one that might fit the bill, but only one.

John

24 August 2003, 04:09

Sabot

Another good pressure solution for handloaders is to buy big and load moderate. For example, I sold my 338 Win Mag and bought a 338 RUM, and worked up loads that duplicated max 338 Win velocities.

I also load the 300 WSM to 30-06 velocities, the 270 WSM to 270 Win and the 243 to 22-250. This last load is also a jump in caliber, made possible by the 55 gr Nosler Ballistic tip.

All of this requires a chronograph, but it is a lot of fun striving for good accuracy, and I have always found a great load. and some times recoil is actually lower than the round that is being duplicated. Its also nice not worrying about pressure and working with brass and barrels that will last forever.

27 August 2003, 16:21

w30wcf

Seafire,

Interesting subject! I don't know
about the bullet manufacturers,
but the powder mfg's. do.
It certainly seems feasable that
bullet mfgr's would use the case
expansion method to determine maximum
loads with their bullets. My guess is
that they also rely heavily on the powder
Manufacturers data.

I have a friend that works at Hodgdon
powder and they definitely have pressure
guns to test the different lots of powder
to be sure they are within spec.

Also, they show pressures in their data
manual as do IMR, Accurate Arms, Alliant
and Winchester.

w30wcf

[ 08-27-2003, 07:25: Message edited by: w30wcf ]

04 September 2003, 10:40

Gunnut 45/454

Seafire
"32 gr, 87,841 psi, 1911 fps, case head expansion .0025", case head separating where case head is flowing into the extractor, action popped open, some leading in the muzzle, and case ejected on firing, primer is spreading out .010"

So why did you stop there? You were at just twice the pressure that rifle is rated for I'm sure you could of went to three times the safe limit? Please tell us how many of these rounds at this pressure you actually shot? What do you do with these rifle after you've stressed them to the point of braeking? Sell them to unsepecitng individuals who are now using possibly unsafe firearms? the curious want to know? [Roll Eyes]

04 September 2003, 19:23

B17G

quote:
Originally posted by Gunnut 45/454:
Seafire
"32 gr, 87,841 psi, 1911 fps, case head expansion .0025", case head separating where case head is flowing into the extractor, action popped open, some leading in the muzzle, and case ejected on firing, primer is spreading out .010"

So why did you stop there? You were at just twice the pressure that rifle is rated for I'm sure you could of went to three times the safe limit? Please tell us how many of these rounds at this pressure you actually shot? What do you do with these rifle after you've stressed them to the point of braeking? Sell them to unsepecitng individuals who are now using possibly unsafe firearms? the curious want to know?

Gun Nut: The post you speak of was not my post or creation. You need to find out who the real author is of that post and pass your observation and " Inquiring Minds" question on to him.

06 September 2003, 11:11

<Greg Langelius>

I either rely on the max loads listed in loading manuals, or, where no such data for a cartridge/bullet/powder combination exists (like I've been doing lately with the .260 Remington for L/R target shooting) I do some cautions pressure testing of my own. I do .5gr increments for Midbore case, .3gr increments for cases like the .223, and hove no reason to test cartridges bigger than .30'06, because I don't shoot anything bigger than that; recoil is not my friend.

The case head expansion measurement is a very good way of knowing when your're getting out of the safe range. To establish that measurement for the cartridge you're going to be testing pressure on, buy (or bum) a factory load, measure it, and fire the round in your chamber. Measure the diameter of the case at its widest point, above the base at the area called the SAAMI bulge or SAAMI ring. That's your safe dimension. If, during testing, the diameter exceeds this by as much as .001", that's telling you you're beyond the factory designated safe pressure. Actually .001" larger is quite a bit beyond safe, but if you see it you know for sure you're running too hot.

I judge my max loads by the basic case reading signs listed above, but I stop firing increments immediately when I encounter bolt drag on opening the action. Above that, I will not go.

Be advised that loads which are OK at lower atmospheric temperatures can become overporessure loads on a hot day. How much, and how fast depends on the thermal stability of the powder being used, and can vary quite a bit with some powders, especially the older grades. The newer powders, many of them, show some improvement in this area.

Greg

06 September 2003, 13:28

Clark

"Speer 6" 1964 38 s&w special 160 gr. soft point 11 gr. 2400

Midway "Load map" 1999 357 mag Speer 160 gr. soft point 10.9 gr. 2400

What went wrong that Midway could get the max loads so far off and make a useless load book with 357 mag loads wimpier than tried and true 38 special loads?

They used an "Oehler System 83 and piezoelectric transducers, the latest in industry standard equipment".

There are two ways to do things, per procedures are per our judgment. Obviously we all do both every day, but the mix varies with the individual. The tendency of many to keep faith in load book, no matter how insane has to be some entertainment to those longer on trusting their judgment.

06 September 2003, 22:32

<BEJ>

I e-mailed Hodgdon because of a "discrepency" between their manual/website and Lyman using H380 in a 6.5x55 with 120/140grain heads. I don't have the data in front of me, but I believe Lyman's starting load, for one of the bullets, was more than the max load used by Hodgdon.
Here's the "answer" I received;

"No, if we shoot the same data on two different occasions, then we get different results. The simple answer is that Lyman got different results than we did".
Thanks,
Phil Hodgdon

What a joke!!!!!!!!!!

11 September 2003, 15:54

Clark

Work up a load until the brass flows.

Get another gun, another brand of bullets the same weight, another brand of brass and primer, and another lot of the same powder.

Work up until the brass flows.

Is the point of brass flow more consistant than the difference between manuals?

I don't know, I haven't done it either.

11 September 2003, 16:58

B17G

BEJ:

Interesting post. However a 6.5 x 55 is not a good cartridge to compare for what one group uses to another. Shooting a 6.5 x 55 I know that loads for it, are sometimes meant for modern firearms, others list load data for the weakest action ever made in that caliber.

You feed back from Hornady is a good thing for all of these guys who come on line here and argue with some of us, because our hands on experience conflicts with what their books on their Shelves say. Most who argue don't seem to have tried to duplicate what one person was saying, so they had a real world point of reference to base it off of.

It makes me wonder if it was 3 oclock in the morning on a desolate 4 lane highway, in the middle of nowhere, without a sole in sight, If someone snuck( sp?) out and put up a Speed Limit Sign that said 20 mphs, how many of these " reference manual" armchair critics, would actually slow down and drive the 20 miles per hour, without giving it a second thought.

However we must remember, the world was also flat, until some " idiot" got in a ship and sailed around the world, without falling off.

Clark: Love your last post Brother!
I haven't tried it either.
[Razz]