Years ago, copper units of pressure was used and many writers interchanged the words CUP and PSI when talking about pressure.
Today, pezio measuring systems give us actual pounds per square inch - thus, the numbers sound high.

Yes - many rounds today list seemingly high numbers, but when you compare those high PSI numbers with the CUP numbers on the same loads, you see the difference.

Here's a chart, showing SAAMI pezio PSI and CIP pezio PSI numbers, as well as the SAAMI and CIP 'crusher' #'s.

Note how some are listed as maximum pressure of 65,000 under the PSI row, and 54,000 under the CUP row, or 62,000 under the PSI and 50,000 under the CUP.

Note the .22 Hornet at the top of the link's list - 46,000CUP, but 53,000PSI!

Note also how some ctgs. on a particular case, ie: .30/06 case is listed so much lower than another round on the same case, ie; the .338/06 - or 35 Whelen vs, .270 Win, or .280- all on the same case, all with different maximums. There is no obvious reasoning, except perhaps WHEN the various rounds were run through testing and when they achieved the ballistics desired, they stopped.

Note the 8mm Rem Mag - CIP max of CIP 67,000PSI! That's the highest, I think, for a factory load.

Now, if your handloads are giving you higher speeds than factory ammo, I have to wonder what your loads actually are producing for pressure?

http://kwk.us/pressures.html