Home Forums Hunting & Shooting Ask The Gunwriters Maximum case Pressures?

You have a modern high powered rifle, say a Ruger Mod 77 or any other factory brand of your choice.

Per QL these rounds have the following pressure listings.

You have a 25/06 factory round listed at 65267 PSI.
You have a 270 factory round listed at 62366 PSI
You have a 280 factory round listed at 58740 PSI
You have a 30/06 factory round listed at 58740 PSI.

Why is there so much difference between these rounds and their pressures, when basically they are all made from the 30/06 (parent case) to start with?

Is the 25/06 and 270 cases made from different brass or harder brass to take the different pressures? I don't think it can be the rifles as they are all MODERN high quality weapons.

You look at all the New Win WSM and WSSM cases in all calibers and they are listed with the same case pressure of 64542 PSI.

Inquiring minds want to know.
Tia,
Don

The SAAMI pressure rating for the 280 is 60,000 psi. Where did you get your info from. Just wondering about your sources?

Different time periods and firearms chambered for the cartridges makes for differences in pressure ranking.

QuickLoad, being from Europe, often uses the CIP standards for pressures.

Ol' Joe's comments explain the differences among these cartridges.

378 Canuck,
I got this info from my 1st ver of QL, I just checked my lastest ver 3.4 and the newest updated files for the powders and bullets and find different psi listed for several calibers.

Per 3.4 ver of QL and Updated powder/bullet disc ver 3.x, I have the following info listed as MAP PSI:

25/06= 65267 PSI=Piezo CIP
270= 65000 PSI =Piezo SAAMI
7mm Rem Express= 58740 PSI=Piezo CIP
280 Rem= 58740 PSI=Piezo CIP
30/06= 60,000 PSI=Piezo SAAMI

If I remember right the 7mm Rem Exp and 280 Rem are the same case, just different names like the 244 Rem and 6mm Rem.

Using the following example, there doesn't seem to be a logical reason for the pressure differeances listed when comparing load data etc.

These are not selected loads, used QL and ran up the load amounts up to get as close as possible to the 84% MAP as listed per QL, when the load data box changes from Yellow color code to the magenta color, I stopped.

270= 65000 PSI =Piezo SAAMI
270 load=130gr-59.23grs-7828SC=3111fps @ 55230PSI=(84% of MAP PSI per QL)

280 loaded to 65000 PSI as the 270 =
280 load=130gr-63.11grs-7828SC=3168fps @ 55228PSI=(84% of MAP PSI per QL)

280 Rem= 58740 PSI= Piezo CIP
280 load=130gr-61.32grs-7828SC=3164fps @ 49922PSI=(84% of MAP PSI per QL)

There is not that much difference between the loads, except some slight differences of powder charges and PSI differences of the 280 loads, given that the FPS are very close on all 3 loads etc.
Tia,
Don

The difference is not every rifle is a modern rifle, so the recommended pressures reflect the history of the rifle-cartridge combinations.

I guess it is about the rifle's strength being the limiting factor, not the brass case. But get a strong modern rifle with good brass and there should be no reason the old .30-06 can't be loaded up to the same pressures as the .270.

To somewhat extend, the cartridge's designation will be a significant factor for case manufacturing.

A case made for max. working pressure of 65ksi must withstand a proof pressure of about 85ksi, so the hardness at the web must be higher than for a 30-06 standard pressure cartridge.
Otherwise the guns leaving factory can be ruined by case failure while being proof tested.

So by that logic a step up from 60 K psi. to 65 K psi. will ruin a Rem. 700? I think not.

Look at the loading books for the 45-70 cart. and see how there are typically 3 sections that talk about loads for different strength guns built in different eras. 7x57 is another case in point, European vs. American factory loads.

The manfacutors, due to liability/tort law issues with older guns available on the street, have pressure specs. that reflect the possibility of use in "older arms".

So if anyone is worried about it why not form '-06 brass from .270 and not worry about the 5 K psi. SAMI difference?

Re: the OP,

Having read some of these replies, I wish EVERYone interested, or having "Views" on this subject would Mill some cartridge case bases into a 180* Cross-section, Compare various cases,and than review their comments.

In the absence of a mill, some good old fashioned Hacksaw and file work will yield a good product.

It's all about the brass, ..........ALL.

GTC

So you are saying that if I cross section a .30-06, .270, .280, .25-06, and maybe a .35 Whelen from a single manufacturer, say Remington, for example, that I would find a discernible difference in web thickness? What about differences between the various manufacturers?

I keep my life simple and 55,000 PSI is where I like to be..the extra velocity is undetectable in the field as far as killing effect or trajectory at guessed ranges and angles as far as I can tell.

Agreed!

Ken O

No

GTC

No, brass cross-section has nothing to with it. It easy to make thicker, tougher brass for most rounds.

Aside from some cartridges having been introduced around 100 years ago )meaning a lot of older rifles are out there) some have exhibited a tendency to larger pressure variations than other. This is why the .243 Winchester and 7mm Remington Magnum have a lower SAAMI rating than similar cartridges introduced around the same time.

Some cartridges were also introduced for lever, pump or semi-auto rifles. Some of these are pretty old (such as the .250 and .300 Savages) and some are pretty recent (.280 Remington and .307 Winchester). These will typically not have pressure ratings as high as rounds designed for bolt-action rifles.

There are some rounds that have a low pressure rating because of the brass, but this is usually due to the inherent difficulties of making small-diameter brass than can stand higher pressures. Examples would be the .22 Hornet and any case based on the .223 head size.

Had to dash off, and just leave that last rather abrupt negative. In response to your query above,....."No" seemed to be a bang on answer, and I hope I can clarify that.


You've listed a close "Family", all based on the same "Basic"....I'm talking about distant cousins, designed for different pressures, by folks that know what they're doing..

Cross section a .45 long Colt, and than a .454 Casull, and you'll start to see what I'm getting at,....Exterior views / dimensions showing them a virtually identical.......

Someone used the .45-70 Govt. as an example,....Rifles, Actions, Pressure levels. That particular cartridge is one I know VERY well. A "458 Magnum Light" it ain't, though a horde would attemp to make it so.

Cross section some .450 Marlin, and some .45 Norma Basic (a nitro rated case), compare it to cross sectioned .45-70 Govt.,.......it'll become quickly apparent that some care and attention has gone into providing a stronger envelope for those who like putting the hammer down.

we can just wind our way down ( or up ) by caliber / bore size, and find Low pressure v. High pressure designs, and I'd encourage you to note that the difference between em' while visible to the nekkid eye, is nonetheless a marginal and "Fine" line.

I like that 55,000 PSI threshold myself.

Best Regards,

GTC

Thanks for the clarification. I based my question on the OP's question on .270 vs .30-06 pressure. I always figured .473 brass was pretty much the same, as far as pressure ratings go.

I read you 5X5,

I think that the very American tendency to milk every last possible ounce of performance out of every damn thing imaginable (Hell, we race lawnmowers) is what worries we old survivors.

In an anything but perfect world, the pressures that we so knowledgeably opinionate about are something we take for granted.

Enter the "Hot" load, in a case prepped on a "Small Base" FL die,.....

Said load, dropped into a very generous "SAAMI max" chamber needs every bit of strength designed into it,.....

That's what I'm getting at.

GTC

I suppose that we're all trying to get lined out in the same direction.

I'll make no bones about being a bit vague on a LOT of the material discussed.

Hope you'll be back to clear off the fog for us.

GTC

Over the last 12 years I have overload worked up to trouble to see what happens in; 19 Bagder, .223, .243, 25acp, 257 Roberts AI, 260, 270, 7mmRemMag, 32acp, 32sw, 32S&WLong, 32-20,.62x25mm, 7.62x39mm , 308, 7.62x54R, 8x57mm, .380, 9x19mm, 9x23mm, 357 Sig, 38 sp, 357 mag, 38sw, 40sw, 10mm, 10.4mm, 45acp, 45Colt, .410, and 45/70.

The 1889 Mauser 7.65x53mm case head design is often used with larger Boxer primer:
Examples: 22-250, 243, 6mm Rem, 250 Savage, 257 Roberts, 25-06, 260 Rem, 6.5x55 [US brass], 270, 7mm-08, 7x57mm, 280, 308, 7.62x51mm, 30-06, 8x57mm, 338F, 358, and 35W.

Those that were Mauser case heads with larger Boxer primer pockets registered with SAAMI at 65,000 psi, and have pre-lawyer loads in old load books may get short brass life with 3 grains over published, but the gun won't blow up.