Elmer Keith and Brian Pearce have reasonably posted their information regarding the subject.
The 1983 NRA handloading guide gives a CUP pressure establishment of 43,500 CUP. Most modern manuals still using CUP limit it at 40,000.
If you don't think their information is based on facts or are lies, or know otherwise, speak up to the contrary. It might make history....
It might also bother you that the 357 Magnum, the 221 FireBall and other cartridges have been loaded up and down over the years, with very few, other than the contrarian, argumentative types to cry bullshit and tone down their rancor when real people corroborate it.
