Horray for eldeguello! He hit tthe nail on the head. I was just reading my Lyman reloading manual last night to kill some time and what he stated is true - as told by actual relaoding experts.
The Maximum loading may not be a true maximum load for a given rifle. All the manuals do suggest that you start at 10% below these "maximum" loads and work your way up.
(Also notice how the newer versions of manuals list a maximum load that is way below ones that they had previously listed in earlier revisions? Must be a liability thing.)
I've been loading now for over almost 40 years and some of my pet loads in a few of my rifles (based on data from very old manuals), the .270 being one, would make a beginning handloader shudder if he referred to data in some of the newer manuals.
These loads show no signs of excessive pressure but I also would not shoot them out of a different rifle without working my way up.
There are several other factors that contribute to excessive pressures or false pressure signs. Excess case lube on cases may make one believe that pressure is too high due to the lube not allowing the case to hold tight against the chamber. Too long a case neck from not trimming cases to proper length, improper sizing.
My advice - Get yourself a good reloading book and actually read it. Maybe you could teach some of the self ordained experts something.