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I'm only speaking in generalities...sorry...but the pressure thing is a big bugaboo. A lot of older cartridges are listed with old pressure ratings, from when they were developed...like say a 46,000 psi...when they could very well go to over 60,000 in todays rifle actions easily. What I do is use the "Load Tech" Type program...enter case capacity data...then use a max pressure of say 59,000. Then look at what powder will fill the case 100% (or near that) & give the most velocity for the same pressure. That should be the most efficient powder then.
You will find that a lot of big bore cartridges ran at fairly modest pressures...
I think most modern (and some older actions) will stand a lot of more pressure than is loaded (as a "safety factor). I have maybe 10 different reloading manuals...and 10 different "max loads". Who is right? Why will one manual have a substantial higher max load than another? And yet, they are still within safety limits.
I think the oldtimers had the best answer, experiment reasonably, and see what works for you...no sticky bolt, no obvious high pressure signs, accuracy with velocity wanted...roll your own & look at the manuals for reference points.
"Illigitimi Non Corborundum"
Best Regards, Tom

Let's be more precise!

The CIP max average pressure for the .404 Jeffery is 52,975 psi. Max individual is 60,929 psi, according to the A-Square manual, which is technically good and not typo-ridden.

The artificial pressure limits set up by CIP or SAAMI are to protect old/antique designs or the weaker materials of the old relics that the cartridges might end up in.

I SWAG that if my loads were shot in the A-Square pressure barrel, they would stack up about like this:

400 grain Woodleigh FMJ/80.0 grains Varget: 50,000 psi

400 gr Woodleigh RNSP/81.0 grains Varget: 50,000 psi

380 gr North Fork SP-CP-FP/83.0 gr Varget: 52,500 psi

340 grain North Fork SP/87.6 gr Varget: 55,000 psi

I SWAG that pressures are even lower in my rifle with a Magic McGowen Micro-Land 10" twist.
My handloads are so much more uniform than factory variances, that I will never exceed the max individual CIP limit of 60,929 psi.

Ditto bisonland. Varget would be the best powder, by his rules, for the .404 Jeffery.

Don't overlook the guns !The 416 Rem is used in modern guns with modern metallurgy. The 404 is almost 100 years old and the modern ammo must be safe in those old guns. Look at the 6.5x55 - SAAMI has recently reduced the acceptable pressures because some of the guns are over 100 years old.

quote:

Originally posted by ALF:

1. Why is is that the 416 Rem case is "rated" by SAAMI as being safe up to a peak pressure of 54000 cup / 65000 piezo psi and the Rigby ( CIP) only 41364 cup / 47170 piezo psi.

In the same vane why the 404 Jeffery only 46444 cup / 52975 piezo psi?

Alf,

When you state the case is rated, do you mean the brass itself?
I don't believe SAAMI looks at the casing for their ratings but at the weakest gun factory chambered in it for that particular caliber and bases the psi on that. A good example is our old .45-70 which I believe is SAAMI rated around 28,000 psi. That said I have shot them at 40,000 psi in appropriate strong guns and never had a casing problem. Some go higher than that.
I can't help you with CIP as I have no knowledge of it.
AC has a point on softer brass, ...maybe, but I doubt it. Most rifle rounds seem to have a hard brass head across the board in my experience. Some could be softer, but I haven't seen them. Norma brass has been softer sometimes in my experience. Sorry, I don't have a .404 for first hand experience. (but have been thinking about it) I have only found revolver cases that were softer in the head.

Of course the larger case diameter will give more thrust; but with a modern strong gun not enough for any problem. I know some load the Rigby well above the CIP ratings you list above without brass problems.

Has anyone expanded a primer pocket with the higher pressure loads tried?

Perhaps one of our metalurgical posters could run a hardness test on some of the various caliber and brands of cartridge heads to see how it compares to the .416 Rem variety?

BigRx

Part of the answer lies in history, part in marketing, part in economics, and part in the basic American genetic drive we call "the need for speed".

The 404 Jeffrey and 416 Rigby were developed a while back to push ~400 grain bullets at 2,150 and 2,300 fps respectively. Given the steels, propellants and engineering knowledge available at the time, and with safety and ease of extraction in hot weather in mind, the decisions were to go with capacious cases/low pressures.

Can modern rifles loaded with more flexible powders move the bullets a bit faster at slightly higher pressures with good extraction and a very comfortable safety margin? Sure.

In view of the presence of old rifles, a litigious populace and a limited market for these cartridges, is it worth getting the specs re-done? No.

Was it a good idea certifying the 416 Rem Mag at 65,000 psi. From a safety, functionality and accuracy point, no. From a marketing stand point Remington wanted to make 2,400 fps with 400 grain bullets. With lead cored bullets no big deal. With monometal bullets, not a good idea at all.

So, what to do? Anyone who is handloading for these cartridges will have to make their own decisions as to how much pressure they think is prudent. With a newer rifle and good brass one could probably load all of these cartridges to 55,000 - 57,000 psi with good functionality and a respectable margin of safety. I personally see no need to go above 60,000 psi in any cartridge. That is my personal decision.

As I develop a line of commercial ammunition what will I do? I will load the Jeff and the Rigby to their original specs. With modern powders I can squeeze out a little more velocity. For people who have original rifles with original sights I will offer ammunition that hits the original velocity spec dead on.

For the 416 Rem Mag I will obviously stay within specs. I will find a load that gives totally reliable function and safety at 120 degrees F after the ammunition has been sitting on a dashboard in the sun for an hour or two. That load will obviously produce much less than 65,000 psi under standard test conditions. It will, however, get the job done in fine style under any conditions.

Safety, reliability and accuracy. What is not to like about that?

lawndart

I have been curious about the 06 based carts. as well. The .270 has always been a hotrod but the .280 runs 5-10K less pressure in most loading sources. I know the .280 was originally made up for a semiauto, but you would think the guys writing the manuals would just test in modern firearms & then put a BIG disclaimer about using the loads in older or diff. actions.

Fred,

You do bring up a good point about the semi-autos. Many of relatively weak operating systems so port pressure must be controlled. This situation however, would not be considerable for the 404 Jeffery, 416 Rigby, 505 Gibbs, etc, etc.

ASS_CLOWN

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Alf-Insurance co and lawyers figure in the
process when case makers and ammo loaders
who form SAAMI etc, get together to set standards.Any chance of a companies loads used in old guns and they back off on the pressure
because their lawyers say so.But as we all know the brass from last 40 years by regular makers is ok, so if you reload for a newer rifle,
one you have had built to modern strength standards, etc. you can go to sensible pressures.Like loading
404 and 416, to 458 pressures.Ed.

So,
What bothers you more, that the 404 and 416 specs call for low pressures, or that many/some/a few in the greater AR community are now loading these same cases to high pressures?

The concern with keeping pressures down to spec for the old rifles is a very valid one. It is for legal reasons. Also, keeping the bullet at point of impact for the old sights requires modest velocities which in turn imply modest pressures.

lawndart

Alf,
How in the world did you then damage your old original .500 Jeffery Mauser?

You said you had set back the lugs and ruined that rifle by following load data taken from this website?

How in the world could that happen?

Was your antique rifle a faulty one that was improperly hardened in manufacture?

You did not blow up brass cases in the process did you?

I think Ed is right. Just the mention of using a certain round in pre-WWII guns triggers low pressure limits.

The pre-WWII steels were heavier and weaker than post WWII steels, I have read from reputable sources. Even "Krupp Stahl" was better after WWII.

Sumbuddy who know metallurgy of this???

/

Alf,
From the _Lapua Shooting and Reloading Manual_:

"The .338 Lapua Magnum case is basically necked down from the .416 Rigby, but reinforced to stand higher chamber pressures of 60900 psi
(420MPa)."

What happened to the .500 Jeffery Mauser?

Pre WWII steels HEAVIER and weaker ??? As I understand the pre war Mausers were made of medium carbon steels, case hardened. Today's receivers are typically made of 4140. but the QUALITY of the steels [fewer inclusions , more consistant composition,better control of heat treat] is better.

mete,
This was stated in the context of double rifles built by the English pre-WWII. Heavier, and not as strong, was said of the old fluid steels.

WWII forced technological refinements that rubbed off on sporting firearms too.

Todays steels are stronger and lighter than pre-WWII steels, it has been said by others, not me. I would like to understand this???

Alf-They built older designed cases to
match older specs on the gun.Most saw no reason to make cases heavier as the gun
held the pressures down.So it gave excuse to make brass accordingly...And it is a real pain
in ass,as I know from experience in finding brass with heavy bases for wildcats...If I asked most brass guys why aftermarket NE cases
and other big ones were built thin in the head,
stock answer was ,gun don't need any more.... it is too old and weak...But when hotrodders
took old stuff to base high pressure wildcats on, they had to beef them up.If I could have found at the time( started in 1990) 450 NE #2 brass with thick bases, my first wildcat would have been built on it(a long straight belted case-called the 470HE), instead of the 450NE brass that I used from Bell with real thick bases;To make 458HE.Ed.

/

Alf,
Lapua Manual: 420 MPa or 60,920 psi

The .338 Lapua Magnum was developed with military applications in mind. Maybe they wanted a tougher case to slam around in a machinegun? I really have no explanation otherwise. Please do not shoot my .404 Jeffery loads in your gun. I know my gun and brass combo can handle it, but I have McGowen Magic Micro Lands with 10" twist.
I am probably getting no more than 55Kpsi.

How about that .375 Wby brass that gets to operate at almost 64Kpsi mean pressure? Is the belt and slightly-skinnier-than-.404-Jeffery case good for something?

Maybe you had an inferior late war Nazi action that was not heat treated at all?

A/

Alf,

Firstly, what Lawndart said in his posting.

Secondly, when pressures for the 416 Rigby and 404 are stated as original then brass and rifle makers are free to make brass or rifles within these limits.

For example, if Ruber only uses a 1" barrel thread on their Number 1 and you load your 416 to full potential and get a swollen chamber you will be on soft ground if you complain.

If you load your 416 Rigby beyond 2350 with 410 grain bullets in Bertram brass then again you are on soft ground if you complain to Bertram about soft brass.

A similar situation exists with the long range hunters using Sierra matchkings and claiming excellent results on game BUT Sierra say they are suitable for game. That statement allows Sierra to change their match kings and make such changes without any consideration to their performance on game. In fact many years ago Sierra match kings were FMJs.

Likewise, Norma might due to whatever reasons one can think of make 416 Rigby brass softer than current brass and also do the same for 30/06 and 404 Jeffery.

Now having said that, if you are Hornady etc and produce loading data that is approaching 416 Wby ballistics (the 416 Rigby is obviously a slightly smaller case than the 416 Wby) and Norma at some stage makes the brass differently, then Hornadys loading data might generate complaints.

I must admit, that while having done plenty of dare devil reloading in my time, if tomorrow I owned a 416 Rigby or 450 Rigby or 500 Jeffery or 404 Jeffery and Norma (or Winchester) made brass for all those calibres I would initially be cautious with my first loading. In other words while case dimensions tell me the 450 Rigby and 460 Wby should be close, Norma or Winchester "just might" make the brass with the 450 Rigby specified ballistics.

So just as Hornady does not know what Norma will do with 416 brass so the gunwriter does not know what Sierra will do with matchkings and hence recommend against them for game use....even if he was using them himself.

Mike

So how come in winchester's wisdom did they decide that the service ceiling on the 30-06 was 58,000 (or was it 60,000) and the 270 was 65,000. We are talking about the same action and the same barrel steel so two identical rifles coming off the assembly line, one in 30-06 and one in 270 are very different in the PSI that will blow up?


I am anxious for someone with a M43 or similar to do some load testing on the 404 and Rigby in some of our warmer loaded cartidges to see what the real pressures are. We can guess at what the pressures are but until we actually test them we will never know for sure. When using a new bullet weight, with no loading data available, what do you use for a yardstick? You are basically in the relm of wildcatting. With a wildcat that you are developing would you logically keep it under 50,000 psi? I don't think so. Can the actions and brass hold up to 416 remington pressures. Likely. My regular hunting loads in both 404 and 416 are way below the top loads I have tested. They are over the original loadings in cordite however.

But Winchester was not the decider of the 30/06 pressure limit. The fact that the M70 in 270 and 30/06 is the same rifle is not relevant.

In the unlikely event that Weatherby chambers their rifles in 416 Rigby that does not change the specifications of the 416 Rigby. If Wby did chamber their rifle in 416 Rigby and Hornady used such a rifle for their loading data they would still stay at 416 Rigby specifications.

An Australian who posts here with the handle PC has a CZ 416 Rigby and he tried Bertram brass and from memory 2500 f/s was too much for the brass. But again, he could hardly complain to Bertram because the brass was OK up to 2400.

Mike

quote:

Originally posted by ALF:
AC:

Calm down! hang on to your Jack Daniels.

I'm not accusing you of anything just stating that you claim things different to what is on ink and paper out there.

So you say it's marketing hype well I just took 3 cases and sacrificed them for science.

the pictures speak for themselves:

It does indeed look like the .338 Lapua web/head is stoutest of all, followed by .416 Rigby, then .416 Remington.

Leaving the spent primers in the Rigby and Remington must be ignored.

The thinner .416 Remington is smaller in diameter too, so maybe that warrants the highest pressure rating with the thinnest case of the three?

Analyze that AC.

I have no idea why SAAMI "rates" some cartridge as being suitable for this or that pressure. However, I DO know why the .416 Rigby is generally factory loaded to a lot lower velocity than its' true potential, which happens to be right up there with the .416 Weatherby, etc! The reason for this is is that when it came out originally, loaded with CORDITE, it was wise to underload big rounds that were intended for use in hot, tropical climates so the fired cases would extract with certainty as you were staring into the face of an oncoming M'Bogo, Simba, or Tembo, B'wana!! The same idea applies to the .404 Jeffry, and a number of other British Big Bores!

El Deguello,
Undoubtedly correct. And with the inertia of the ages, why try to redo specifications? It would never happen!

Any artificial brakes on the .338 Lapua Magnum pressures might come from the original intention of using this cartridge primarily in military roles, like sniper rifles and even full autos. Heat and dirt in hostile environments?

However, read the specs I posted above, y'all. They ain't as low as Alf is saying. According to Lapua: 420 MPa or 60,900 psi average chamber pressure.

quote:

Originally posted by D Hunter:
So how come in winchester's wisdom did they decide that the service ceiling on the 30-06 was 58,000 (or was it 60,000) and the 270 was 65,000. We are talking about the same action and the same barrel steel so two identical rifles coming off the assembly line, one in 30-06 and one in 270 are very different in the PSI that will blow up?

Here is a good example of SAAMI at work. The relatively modern .270 (if we can call 1925 modern?) has never been manufactured in a gun of questionable strength. While the old '06 has Winchester 95's (original) and low number '03 Springfields to name a couple that warrants in SAAMI's eyes to regulate a lower pressure to ammunition manufacturers!
It makes no sense to a brass manufacturer to use a different casing for .270 and the .30-06 either. The process of manufacture for the two is identical up to the last couple of steps that make it either one or the other. (or a .280 or a .25-06 or a .35 Whelen) you get the idea.
I don't think the "rupture" strength of the older guns is in question as to older Mausers and such. But YIELD strength could very well be. While early bolts were probably still stronger than anything we would ever feed them they don't compare to modern heat-treated Chrome moly (4140) or 400 series stainless alloys with tensile strengths of 160,000 lbs. per cross sectional square inch and beyond.

Cartride brass has been "improved" over the years as well! Two extreme examples are the .22 Hornet and the 7mm x 57.
Alf's nice picture shows us a common web configuration change that is taking place that has a rounder bottom to lessen perpendicular stresses at the web area in my opinion. This is good for us all, but it doesn't mean SAAMI is going to raise the limits! The .454 Casull is a souped up and longer .45 Colt that runs pressures into the 60k's. Federal .45 Colt brass is almost as strong. Better not go 50k in your old Peacemaker just because the brass can take it though!

/

Alf,

sometime back i was wondering similar question and traded emails on the subject. Do not know if this is the case, but...

"I agree regarding brass and action strength. But I did a study a couple of months back that makes me wonder. Using the A2 manual, I wonder why the 505 is lower pressure than the 416 which is lower than the 375HH. I think all these were developed around the same time, similar brass and actions, so why not the same pressures. At about this time the forum was having a discussion on bolt thrust, so Iooked to see what I could find out. I assumed the web designs were similar and used the extractor groove dia. as the area for the thrust for want of any better data.

Here's what I got:

375HH, groove dia.= .475 (.512 head size) gives a bolt force = Area*62000=10987lbs
416rigy, groove dia= .500 (.581 head size) gives a bolt force =Area*47100=92618lbs
505gibb,groove dia= .555 (.640 head size) gives a bolt force = Area*39167=94754lbs
470Mbg,groove dia= .500 (.589 head size) gives a bolt force = Area*49000=96354lbs

In that discussion, some mentioned that the cz550 action was rated for nominal force of 9700lbs (maybe 10700), which matches well with the above if we assume that the older actions had similar rating. So I wonder if the old cartridge designers used something similar to get their pressure rating." and then designed the cartridge web. The 404 seems to be an anomaly.

rgrds,

steve

OK - I say we all pitch in and buy a piezo transducer and put an end to all pressure debates by actually testing the cartridges/loads...

Who's in?

Been there done that!

I strongly recommend them though. When coupled with a thorough understanding of statistics, it open a whole new world (it exposes some very interesting facts, to put it politely).

ASS_CLOWN

quote:

Originally posted by new_guy:
OK - I say we all pitch in and buy a piezo transducer and put an end to all pressure debates by actually testing the cartridges/loads...

Who's in?

But to expect piezo pressures to be accurate for all rifles other than the one rigged for pressure measuremnet is folly. It will be only an approximation, a place to hang one's hat. Will the transducer be rigged up for every rifle owner who chips in then? The traveling piezo? Compiling all the data from many rifles would indeed be more meaningful.

Ron,

That is where the wonderful world of statistics come into play. Believe me the results of strain gaged barrels isn't folly. The more rifles firing identical loads are measured the more accurately the distribution is defined. Also, it has been my experience that the pressures don't move around as much as many would have us all believe (typically staying within a range of 5000 psi and usually far less.)

ASS_CLOWN

quote:

From ALF:

Thank you ever so very much, Alf. Buy a donkey!

It is amazing how strong the Norma .404 Jeffery case looks. Almost as good as the .338 Lapua Magnum.

The piezo transducer is still overridden by the brass.

Eg. Load a 416 Rigby to 2550 f/s with 400 grain bullet and your piezo transducer will tell you that your pressure is moderate. After that, put those loads in some Bertram 416 Rigby brass and instantly your moderate piezo transducer readings are a waste of time.

The Australian poster PC tried Bertram 416s and the brass was history at 2500 f/s

Mike

Then a standard load from one source would have to be tested in many rifles, eh? Then an aggregate mean pressure and standard deviation would have some meaning.

No Bertram brass allowed!