What's with Sub-SAAMI 'Max' Loads?

[ChristopherG]

I load 41 mag with Win 296 powder, and my question arises from data regarding that combo; but it's really a more general question:

What factor or factors lead manufacturers to publish 'max' recommended loads that are well below SAAMI standards for peak pressure?

E.g., Winchester publishes a 'max' load for the 41 mag of 20.4 grains of 296 (w/210 JSP); but they indicate that this only generates 24,000 C.U.P.. The load just above this on their data sheet, a max load for 231, generates 38,000 C.U.P.--a huge difference in pressure! Other published guides list loads for 296 with this same bullet style as high as 22.9 grains. So why would Winchester publish a load so far below maximum pressure as their recommended 'max'?

I'm hoping to get at an answer beyond 'lawyers', here; if it was simply a concern about liability, wouldn't they back ALL their recommended loads down to similar pressure levels? Here's hoping one of you smart guys or gals will know what's behind this strange behavior, and thanks for trying

cg

 

[WESHOOT2]

BETTER ANSWER

A story:

So I'm working up this 357 load using a 180g JHP hoping it will prove adequate for deer.
I test it in my two KGP-141's, and they both show good accuracy, with one shooting about 20fps slower.
Then I test it in my 7.5" Redhawk.
I get 100fps more.
And I get another treat; it blows the primers.
Not one, but every one.
Back in the KGP's and it's fine, swap back into the Redhawk and they blow.

There were no lawyers involved in the making of THIS ammo.



(ps I got some on my shelf still; you wanna test some?)

 

[griz]

A couple more possibilities:
1. Maybe they can't get enough 296 in the case to get up to max pressure.
2. It's possible the pressure they list is an average pressure, but the load can cause enough variation to get to max pressure on some individual shots.

 

[caseydog]

Or maybe thats the highest pressure the round was "stable" given their component choice. Could be they went to 21gr. and started getting wild pressure fluctuations. Ray