On the contrary I have had many bad experiences with Norma because it was too hard. I have had Norma brass split on me in the neck many times due to a lack of ductility. Obviously I should have annealed (softened) this Norma brass prior to loading. The problem is that this was a very hit and miss problem. Out of 100 Norma cases only one or two exhibit the problem. The others work fine for 5 loadings and them need to be annealed (do to the cold working of the sizing operation they have hardened). This is acceptable to me and expected. It is the fliers that bother me.

So is the Norma brass crap? Or, do I need to first anneal the Norma brass making it effectively high quality Bertram (read soft brass).

Your opinions are appreciated.

Todd E

To my knowledge Weatherby has always been loaded by Norma. I remember hearing those same rumors however. I have not owned a Weatherby rifle in close to 20 years so I cannot comment on their new stuff.

The Norma brass (at least the stuff I have had in the last year or so) has been much harder than Winchester, Federal, Remington, and Bertram. It likes to split, which is normal for hard brass.

If the brass was left unsupported the stresses induced upon the brass by a 50,000 of breech pressure would rupture/crush any brass now in existence.

Again I have not noticed either. Long sloping shoulders seem to be more condusive to case stretching than brass hardness, at least in my experience. With sharp shoulders I have seen very little case stretch. In the 416 Rigby for instance using Norma, Federal, and Bertram brass none of the cases stretched much (or anyone worse than the others) even when loaded to achieve 2710 fps with 400 grain solids. I assure you the brass hardness was noticeably different between the manufacturers.

Todd E

Because it is soft.

"all the brass is completely supported by the rifles chamber"

Incorrect, long running argument between Mauser action fans and "3-rings of steel" fans. Check reloading manuals. Remember the extractor groove?

"since it will flow more easily"

That is the problem.

"Why do the primer pockets expand?"

Because the brass is soft.

"The primer pockets are typically in the strongest portion of the case (thickest section)."

Correct but if brass is soft they will expand.

"If the brass was left unsupported the stresses induced upon the brass by a 50,000 of breech pressure would rupture/crush any brass now in existence."

Again, check reloading manuals, not all of the case is supported.

"Long sloping shoulders seem to be more condusive to case stretching than brass hardness,"

The .220 Swift shooters will readily agree with you.

All of your questions can be answered by a perusal of basic reloading manuals.

------------------

The portion of the case which is not supported by the rifles chamber in a Mauser is essentially a solid disk of brass. Section a case if you do not believe me. Therefore, the case is supported by the chamber radially and the bolt face. The three rings of steel is merely marketing hype.

Reloading manuals will not answer these questions. If you believe they do why don't you post quotations for me. Since I am an illiterate LEO you could be of real assistance here. By the way, I am not trying to champion Bertram brass either. It has to be the worst quality brass I have ever used. The issues with Bertram have all been dimensional however, not material.

Todd E

Incorrect

"The three rings of steel is merely marketing hype."

Correct

"Reloading manuals will not answer these questions. If you believe they do why don't you post quotations for me."

I just took my Sierra manual over to an acquaintances house. You would find your answer between pages 58 and 70 I believe, there is a photograph of a sectioned case. You can quite easily see the surface I am referring too.

"Since I am an illiterate LEO you could be of real assistance here"

Certainly.
We will use the formula for computing the area of a surface of revolution.

Looking at a C.I.P cartridge case drawing for the .378 Weatherby, the maximum diameter at the base of the extractor groove is 0.4949", the maximum diameter at the belt is 0.6035", a difference of 0.1086". Excellent.

The formula for an area of the surface of revolution is:

Area of Surface = (Integral from a to b) of 2Pi(y)times[(all under the sq root 1+(the derivative of y with respect to x)^2)]dx

So, since the angle formed from the base of the extractor groove to the top of the belt is 45 degrees, this is the same as drawing a line: y=x, this makes it very easy for us.

S=(Integral 0 to 0.1086) of 2Pi(x)times[(sq root of 2)]dx

Take the 2Pi (sq root 2) out in front of the integral and integrate for "x" gives us:

S= 2Pi(sq root 2)[x^2/2] from 0 to 0.1086.

This gives us a surface area of: 0.05234 square inches which is not supported by anything. A good way to see this is to look at a reloading manual that has a cutaway drawing of a case in a full length sizing die, the Sierra manual #13 has such a photograph.

[This message has been edited by Roger Rothschild (edited 04-15-2002).]

What is the thickness of this section of brass. The brass is subjected to chamber pressure no more no less. Your example by the way is applicable to all rimless cartridge firing firearms.

So your argument is that we will have plastic deformation through the section between the extractor groove and the base of the cartridge. Okay I will play along.

How does that cause oversize primer pockets?

Is the internal or external dimension of paramount importance? Your analysis was based upon the external dimension, I believe.

How is the load distributed across the internal surface of the case?

What is the weakest part of the cartridge?

What are the yield strengths of hard and soft ordnance brass?

What effect if any does minimal body taper (common on modern case designs) play in stiff bolt (hard to open)?

What part if any does repriming of brass during reloading play in oversize primer pockets?

Finally, how do you know if you brass is soft or hard?

What is your discipline? I am only curious you need not answer.

Todd E

[This message has been edited by Todd E (edited 04-15-2002).]

[This message has been edited by Todd E (edited 04-15-2002).]

And:
"So your argument is that we will have plastic deformation through the section between the extractor groove and the base of the cartridge"

At no time did I ever say any such thing, I only stated it was unsupported.

I am in my fourth year as a chemistry and biochemistry major at the University of Alaska Fairbanks. I was interested in going on to medical school but that would take another seven years. I have decided to go into the Physicians Assistant program at Univ. of Wash. I haven't yet decided on the Masters program or simply the two year program. I will continue on with my first interest in chemistry. Once I get back to Bethel I will build my own lab and continue doing research.

quote:

---

Originally posted by Todd E:
To me the soft brass should be better since it will flow more easily and not work harden and split as fast. The act of annealling is by definition softening the brass.

---

Todd E:

Reread Tailgunner's post. He has it right. Remember that annealing will only soften the neck/shoulder area. Thus eliminating the splits you have seen. But I want the base of the the case to remain hard to minimize sticking to the chamber. Annealing accomplishes the desired goals without softening the case head if done properly.

I find it intersting that you too have had problems with Norma brass splitting in the necks. I use Norma for 7x64, 7x65R, 308 Norma Mag, 358 Norma Mag, 9.3x62 and 9.3x74R. I have had quite a problem with the brass splitting on a few cases after the first shot with new brass. It made me mad enough that I even tried to return some examples to Sweden, but I never got a response from Norma.

Everyone writes very glowingly about Norma brass, but I only use it out of necessity for my more obscure calibers. I have taken to annealing all new Norma brass before the first loading. It's too expensive to risk losing cases to neck splitting.

soft brass = rim pulling off case while the case is still in the chamber (at ordinary pressures).

Anyway, the cartridge case follows the expansion of the rifles chamber. This is a fact. If the rifle's chamber expands too much a brass case will rupture. The thickness of the brass is more important in many instances that the hardness of the brass. A soft case will not stick in chamber any easier than a hard case at safe pressures. This is because the chamber of the rifle is not expanding too much.

Cartridges like the 500 Jeffery and 585 Nyati will produce sticky extraction at rediculiously low pressures not due to brass hardness, but to a lack of body taper. These two cases (mere expamples of many others) have very little body taper. A 505 Gibbs on the other hand is a beautiful graceful cartridge that extracts wonderfully do to it's large amount of body taper.

Now for the doubters I have gone to the trouble of measuring two sectioned cases and calculating the stresses in the brass.
The cases are a 308 Win and a 416 Rigby.

Operating pressure: 60,000 psi.

Body stress:
308 Win = 344,570 psi
416 Rigby = 443,825 psi

Stress of the unsupported extractor groove:
308 Win = 50,945 psi
416 Rigby = 66,510 psi

The 416 Rigby load has been used with Federal, Norma, and Bertram brass. It is essentially a hot 416 Weatherby load.

It should be obvious that the stresses in the bodies of the cases are far above the ultimate strength of any brass (heck steel for that matter). This is further proof of my statement that the brass simply follows the rifle's chamber expansion.

Todd E

I used to build, service, and calibrate material testing equipment so I had to understand the process (at least from a practial standpoint)

If you want to see soft brass in action, anneal the case head and load with your normal powder charges.

If you do this I would strongly advise that you pull the trigger with string from some distance and also use a rifle that you don't mind having the bolt face burned somewhat.

The case will look like it was fired with a massive overload.

Mike

Since the brass follows the rifles chamber it does not explode! It will however take a slight set! This set is due to the small hoop deflection that the rifles chamber experiences.

Mike375,
I have fired Bertram brass at the aforementioned load without incidence. Everyone here says Bertram is too soft. To be honest I doubt that annealed brass would be much of an issue in either of these cartridges if loaded to 50,000 - 54,000 psi for the 308 Win and 42,000 - 45,000 psi for the Rigby.

Are you familiar with strain energy dynamics? An example would be the forces that a human torso experiences when involved in a car accident. At the time of the initial impact there can be forces up to 200 g's. Obviously a force of 200 g's would cut you in half (the seat belt being the blade). The seat belt also cannot withstand a 200 g loading. Miraculously however neither the human torso nor the seat belt fail during the impact. This is due to the fact that the load is exerted so quickly. Think about it for a while. The same thing applies to the brass. Even if the unsupported portion is loaded above yield and even ultimate strength the load is applied so shortly that the case does not fail. Blown primers are a separate issue from brass hardness by the way.

Todd E

Try this.

Pull a 308 factory round apart and then anneal the case head.

Reassemble with components and then fire and watch the result.

Again, I would advise that a string be used to pull the trigger.

Afrer you have done this you can come back and tell me a about strain dynamics

Mike

PS After this experiment you might change you mind about blown primers and brass hardness.

[This message has been edited by Mike375 (edited 04-16-2002).]

And what, exactly, are your trying to teach me?

Mike said: "After you have done this..."

Hmmmm... Seems like an ounce of doin' is worth a pound of thinkin'...

Rick.

Unfortunately I do not have any 308 that I can pull and anneal (it is all berdan primed). So what I will do is the following.

I have some Federal brass 416 Rigby that has been fired 8 times. I will anneal the entire case and load it up with 110 grains of Rel 19 and a 400 grain Hornady. WARNING: this is a pretty hot load so do not try this at home!

I will fire it in my rifle and report out on what I find!

Roger,

It is obvious that you think you know far more than me. This is unfortunate as no one knows everything. I was merely trying to get you to question the status quo as it is far too often wrong. Instead you insulted me because you feel that LEO are idiots and you are far smarter. I have posted the actual load facts! These values were calculated by a good friend of mine who is a mechanical engineer with many many years experience in the auto industry. He has some impressive creditials of his own (as does your professor). I must say that the stresses I posted are average stresses and occur only at the peak chamber pressure. The time at pressure is extremely short. For this reason i will get a good laugh after I run Mike375's experiment. If the chamber of rifle was annealed to a point to some ridiculously low strength I would be afraid.

The blown primer is do to excessive pressure, which is exerted upon the primer itself via the flash hole in the case. The primer will flattening will follow the bolt face delfection.

Todd E

In all likelyhood it will severly damage, if not destroy, your rifle. Hope you don't like it much. Be very, VERY far away when you pull the self destruct lanyard.

You need to get a copy of "Hatcher's Notebook"

I predict:

Mag parts blown out
bolt fused shut with with melted brass
firing pin broken
stock splintered
locking lugs set back
Scope destroyed, if you leave it on

Be sure and heat the case head until it glows, then tip it into cold water. That will make it real soft!!

Here is what happerns. The bass flows and gives way. This allows huge amounts of gas to act on the bolt face. It does so over a larger area than the intact case head allows. This is how a Colt Ace device works, by the way. The chamber bushing slides back and makes a larger surface area to for the gas to funtion on. During WWII there was successfull research at making 30 cal machine guns function on 22 lr cartridges, this way. Getting back to your bolt gun.......by allowing the gas to work on the whole bolt head you are increasing the backthrust tremendiously. If you will ever get an action to shed it's lugs this is the way to do it. This is the surest and most effective way to destroy a rifle so have at it! For God's sake don't fire it in you hands.

[This message has been edited by scot (edited 04-17-2002).]

What will happen is a badly blown primer and very heavy ejector mark. Damage to the rifle is likely to be confined to a burn on the bolt face.

The give away is that the primer itself only shows normal pressure.

We usesd to see is a bit at our rifle range many years ago when annealing cases seemed to be in fashion. A shooter would come up to you with big pressure problems but he only used the loads in the manual.

However, if the load used was already right at the top end, then your description of the outcome would possibly occur.

Mike

Anyway, I have ten 416 Rigby cases annealed. I figured why do only 1. This way I have a statistically significant sample size. I think I will load them with 112 grains of Rel 19, which is the max load listed in Lymans for the 416 Weatherby Mag. That should get me over 60,000 psi. Hopefully I will be able to touch them off tomorrow night.

If I don't post it will be because something terrible happended. I think you guys will all be greatly disappointed though.

Todd E

Kent

I don't think we have the same defination of "annealed".
1. heat the case head red hot with a propane torch.
2. immediately drop it in cold water.

It will now be "peanut butter" soft. Try it that way!! I am NOT talking about softening the necks a bit.

P-207 "Hatcher's Notebook"
....If one of these should have the head heated after it is formed, the head may spread and the primer pocket open out during the stress of firing , and damage to the gun may result. Thus in cartridges a soft head is a dangerious defect."

But hey, you know more than J.S. Hatcher.

The load was 112 grains of Rel 19, 250 CCI primer, 400 grain hornady soft point with annealed Federal brass. The brass full length annealed by the way I DID NOT JUST ANNEAL THE NECKS. Primers did not appear to be anymore flattened than normal. There was no smearing or cratering. This brass looked just like the rest of the Federal brass did. That brass had only been loaded with 110 grains of Rel 19, CCI 250 primer, and 400 grain Hornady soft point.

The rifle was a Ruger M77 MkII Magnum 416 Rigby. Sorry to dissappoint Scot. By the way ordnance brass in an entirely annealled state still has a yield strength around 36,000 psi. Considering that the peak pressure is applied for all of about .5 milliseconds and it is difficult to believe the doom and gloom Scot is talking about.

Here is the best part. I shot all ten from the shoulder NO STRINGS! So much for think about it versus do it! I thought I did. So what is the problem with soft brass?

Todd E

From your posts:

Primers did not appear to be anymore flattened than normal. There was no smearing or cratering

Why should they be any different?

As I said in one of my posts the give away that case heads have been annealed is normal looking primers but the cases have greatly enlarged primer pockets.

Maybe you have steel headed cases and don't know it or maybe your Re 19 is really balck powder

Mike

[This message has been edited by sdgunslinger (edited 04-18-2002).]

Many of the shooters in The Australian Big Game Club are going to be pleased to know that it was not a case of Bertram brass being soft but rather a case of their chronographs reading slow.

Obviously the same applies to A Square brass.

I just feel sorry for Mitch going to all the trouble to get the Horneber brass for his 577 T Rex when it was just a case of his A Square brass causing low velocity readings.

Mike

I have decapped the cases. They seem to be as tight as the other nonannealled cases that have been shot with a lighter load.

I am sorry if I offended anyone with this experiment. The facts are still the facts.

With regard to Bertram brass. I have checked it on a hardness tester and it was very close to Federal. I believe the problem with Bertram is not the hardness of the brass but the piss poor dimensional control. Section some of it if you want. The brass in not concentric, the wall thickness varies all over the place. I have had extractor groove with up to .015" run out, etc, etc. I have had sticky Bertram cases, but not due to excessive pressure. It was due to excessive pressure variation around the surface of the brass i.e. localized high pressure areas.

I knew that there would be no problems with this loas as I had shot it before in this rifle, and I have probably shot thousands of rounds through a 30-06 with fully annealed cases and 2700 fps with 190 BTHP Match bullets. If you still want the hardest brass go for it. You can split your necks or anneal them all the time. Whatever floats your boat!

Todd E

Now I really, sincerely, no sarcasm intended would like to know what you mean by this, i.e., how did you determine pressures varying inside a container. It is my understanding a gas exerts pressure equally in all directions.

You of course are correct. I apologize for my misuse of terminology (remember I am a LEO and we aren't too smart). I meant to say that the stresses in the brass are not uniform; therfore, there is localized high pressure contacts between the brass and the chamber wall. This in turn increases the friction and the effort required to turn the bolt.

Todd E