Another thing on pressures is how it was determined and listed, CUP( copper units of pressure) or PSI ( pound per square inch). The CUP was obtained using the crusher method. In the recent 10-15 years or so with the event of strain gages (piezo-electric) some cartridges have been updated to the PSI figure.

From a Shooting Times article...
We seldom saw these effects in rifle cartridges. Most standards for bottleneck cartridge chambers place crusher and transducer ports much closer, at least as a percentage of total chamber length. We shot transducer pressures for .30-06 loads with the various styles of Speer 180-grain bullets, data for which had previously been developed on crusher only.

The crusher loads were set to max between 47,000 and 48,500 CUP, just under the SAAMI max of 50,000 CUP. Transducer testing showed that the same loads fell between 56,700 and 58,500 psi, just under the 60,000 psi limit for the same cartridge. No changes in published data were needed. Across the range of modern rifle cartridges, we did not find any surprises when we added transducer data to our existing files of crusher data.

Transducer testing provides a direct payoff to the hobby reloader: volume of data. We had to budget 50 percent more time when developing loads that still used crusher standards. Transducer testing let my team greatly expand the coverage in the latest Speer manual.
So the published pressures depends on how it was determined and if it was updated to reflect the PSI figure or listed as the old CUP data. It still boils down to staying within the recommended loading data for a bullet and powder combination for a particular cartridge.

In any event without the equipment you'll only have an approximate idea on pressures. I have had times when the loading was increased with noticeable signs of the pressures increasing while the chronographed velocities decreased.

In other words, load a 308 Winchester as a 308 Winchester, don't try to turn it into a 300 Win Mag! ;D

http://www.shootingtimes.com/ammunit...905/index.html

Bill