The reason I wanted to know was to have some set maximum in mind, especially when playing around with different powder, bullet and even primer combinations.

The GS bullets for example, will give more velocity with the same powder load than with non banded bullets. With a claim from GS of less pressure.

I can get the PSI information for most other calibers and rifles, but not for nitro rounds.

What got me thinking about this was when I looked at Norma's reloading guide for their recommendation for the use of MRP-2 powder in a 470 NE using 128 grains of powder with a velocity of a little over 2200 fps with 26" barrels.

I have a program called quick load, and when you plug the Norma data in you get red warnings all over the place - 15% compacted charge, serious over pressure, warning warning.

Talking to Norma, their charge produced a little over 36,000 PSI. In a bolt rifle, that is nothing. But without any baseline data on a nitro round, that is a number in a vacuum.

I expect that more manufacturers will either start publishing or provide on request the PSI information for rounds, if for no other reason than their damn lawyers will probably make them do it.

So can a double handle 20,000, 30,000, 40,000 PSI or higher? When I have a program that screams overpressure, but someone like Norma saying 36,000 PSI is safe, which way do you turn?

It would be nice to use a slow powder that fills up the case and is accurate. You don't find out the accuracy part until you get to the range. It would be nice to have some guideline to avoid blowing up a nice double.