My interest in reseraching thus subject was piqued by a post in another forum where the poster claimed he was loading Lapua brass to 80000 psi for the first load and 70000 for several or more subsequent loads. Ignoring the potential that this is pure male bovine excrement, I started Mr. Google on a search for information on the subject of ultimate strength of cartridge brass. Along the way I found the highest recommended pressure was by the CIP at 68000 and a bit for the Lapua 300 magnum. This cartridge is not being commercially produced but it is a. 338 Lapua necked down to take 30 caliber bullets. Now said poster justified his post by suggesting that Weatherby once loaded some of their magnums to 75000 psi but I haven't been able to locate any reference to verify this. Does anyone have a reference I can review or maybe have some personal knowledge to share on the subject. So far, from what I have been able to glean from online articles, standard rifle brass will fail around 80000 psi or thereabout.

I just grabbed my book "Modern Handloading" by George C. Nonte jr and it states proof loads in the USA are 72,000psi, this book was printed in 1972. I will read the book again probably this weekend cause I do remember somewhere reading that cartridge brass starts flowing at 68,000 psi.

I'm curious about how he kows what pressure he's loading to. Does he have his own strain gauges, etc?

I see that cartridge brass is C26000 and there are a lot of sources for information about its properties. Might be something in there to answer your questions.

After a quick search the highest pressure I see listed is 71,000 PSI for the .270 Weatherby. en.wikipedia.org/wiki/...rby_Magnum

C.I.P has been around since 1914 and SAAMI since 1926. I kinda figure that they know what they are talking about...

You fellas better be quick, the rate he is going that loopy loader wont be around for long.

And this is the way people get those cute nicknames - Lefty, Ole' One-Eye and etc.

SingleShotLover wrote:

And this is the way people get those cute nicknames - Lefty, Ole' One-Eye and etc.

Exactly, here's another link with pictures of brass loaded to different pressures.

stevespages.com/diagno...blems.html

What is this gentleman's name? so I can make sure I never by a used rifle from him.
The strength of the brass is a minor consideration. I would worry more about the metal fatigue in the locking lugs on the bolt.
I know a guy that is a couple of years younger than I, that lost half of his face when the locking lugs on a Remington 700 let go while firing some factory loads. It had (from the story I heard) been used to "experiment" with some loads in the 7mm Mag.

It is intersting to note that I still can't find a reliable reference to Weatherby pressures. I have found out however that, after SAAMI finally set standards on their cartridges they were all within normal ranges for the calibers involved. Some have suggested that Norma, who apparently makes Weatherby ammo, loads to CIP standards. I checked these and they also remain in what I would call a normal range for the calibers, albiet they vary +/- from the SAAMI. Finally I read an interesting short discussion on the calibration of piezoelectric pressure measuring devices. A number of years ago several calibration standards were in use. Now a common standard has been set and accepted by SAAMI.

Here is a good article that helps explain some things about rifle brass that makes me pretty confident about 80000 PSI being the point where cases will start failing even on the first loading.

www.longrangehunting.c...rust-1.php

BTW I have stopped participating in the other forum. It appears that none of the regular and long term members see anything wrong with the potential that the poster's pressure claims may lull some inexperienced loader to injure himself or others. Thank the stars (and Dallan) there are sane places online like our forum.

I got to tour the ballistics room at Hodgdon Powder a couple of years ago. As a reloading fanatic, it was like visiting Mecca…

The pressure guns they use are just a chamber and a heavy bull barrel. As reloaders, we have all heard of CUP—copper units of pressure. Well, they actually use small copper ‘cups’, (maybe as big as a large rifle primer), when they are working up loads. When the small copper cup is crushed by the pressure of a certain load, they are at the upper end of the pressure scale. I believe they have different copper cups that crush at different pressures—it was fascinating.

Like Bob Hodgdon indicated, it is an old way of doing things, but still works well.

MacD wrote:

BTW I have stopped participating in the other forum. It appears that none of the regular and long term members see anything wrong with the potential that the poster's pressure claims may lull some inexperienced loader to injure himself or others. Thank the stars (and Dallan) there are sane places online like our forum.

I'm just glad all YOU guys like it here. We're still small compared to other places but we definitely have better members, its very rare we ever have the type of strife and drama other sites trip over. That is a testament to the quality of folks here.

Really enjoy the members from all over the globe too, its interesting to hear how hunting, reloading, gun laws are in other regions of the globe.


-DallanC

DallanC wrote:

MacD wrote: BTW I have stopped participating in the other forum. It appears that none of the regular and long term members see anything wrong with the potential that the poster's pressure claims may lull some inexperienced loader to injure himself or others. Thank the stars (and Dallan) there are sane places online like our forum. I'm just glad all YOU guys like it here. We're still small compared to other places but we definitely have better members, its very rare we ever have the type of strife and drama other sites trip over. That is a testament to the quality of folks here. Really enjoy the members from all over the globe too, its interesting to hear how hunting, reloading, gun laws are in other regions of the globe. -DallanC

+1 couldn't agree more .. Theirs a good group here

Thanks Dallan...but don't leave yourself out mate...YOU DA MAN.

Yep, great site, great people, thanks Dallan.

80,000 psi would be taking more than brass past its failure point, I'm not sure what pressures firearm manufacturers proof test their actions at, and yeah different actions will have different proof pressures, but general engineering usually uses a failure load 3 x working load.
SAAMI and the various ammunition manufactures state limits for loads for a reason, best listen to them.

Hey Weirsey,
On a separate topic, any idea what the pressure in the 120 mm gun on the Abrams is?

when I saw 80,000 psi, I just about croaked. Just for reference, I've been exploring ways to gauge overpressure situations beyond just primers and swipes (typcial of semi-autos) by measuring case head expansion.

www.huntingnut.com/ind...+expansion

I agree with Loke, its not brass I'd be worried about. Other components could be weakened and break. One of the reasons I was looking at case head expansion is I broke a bolt in my 6.8. The bolt wasn't from a top manufacturer but I'm sure it was good for standard pressures. Primers and swipes weren't that bad but the felt recoil was sure noticable.

I'm sure he could fire some a 80,000, but one day, maybe when the temps are up, things are going to come apart. I hope other members on that forum aren't following him.

[quote="dhc4ever"]Yep, great site, great people, thanks Dallan.

80,000 psi would be taking more than brass past its failure point, I'm not sure what pressures firearm manufacturers proof test their actions at, and yeah different actions will have different proof pressures, but general engineering usually uses a failure load 3 x working load.
SAAMI and the various ammunition manufactures state limits for loads for a reason, best listen to them. /quote]

Here is a nice little article on proof testing.
firearmshistory.blogsp...-test.html

While not specifically noted, proof testing in the US and Canada is voluntary as are all the SAAMI standards. Based upon the CIP standard the proof test for a 270 Weatherby would be 80000 PSI (64000+16000) wihich is 25% above maximum average approved pressure. Steel cases are used for proof tests except for low pressure chamberings. Surprised that rim fire rifles have a higher test requirement. Another interesting little fact I discovered is the ammunution sold in CIP countries also has to pass a standards test based upon the CIP standard for each calibre. While Sweden is not a CIP country, it would be likely they would load to CIP standards rather than having different production setups for standard and non-standard ammunition. Weatherby ammo was/is proprietary and Norma makes it. Would they therefore not produce all the ammo to CIP standards as higher loaded ammo would not be allowed in CIP countries?

Another very interesting link.
kwk.us/pressures.html