The data you cite was taken from a 240 gr. SP Remington load fired from a 4 inch vented, pressure test barrel, not a 6.5 inch revolver barrel.
Some of the original factory swagged lead, 240 gr. ammo was loaded beyond the pressure standards of 40,000 CUP. Winchester, for instance ran a lot like that. It tested at 45,000 CUP.
But the standards have not changed. It's still either 36,000 psi or 40,000 CUP.
The loading companies have learned to publish better, more accurate loading data because their testing equipment is now more accurate. Capable of recording sudden spikes, not averages as before. In other words, some of the older data was too hot. Rifle data has shown the same trend. E
