Quote Originally Posted by Haiku_Rodney View Post
I push my 150 gr Speer SPBT with 59 gr of H4350. My old Hodgdon manual lists a a velocity of 2968 with a 165 gr Sierra SPBT. I just checked the Hodgdon website and the loads they list for H4350 are a bit lighter. Don't know what to tell you. My loads do not show any high pressure signs, but you may want to start a bit lower and work up.
Loading data for the 30-06 is conservative due to all the older rifles still being used. (60,000 psi and lower like the Hodgdon site)

In a modern bolt action the 30-06 can be loaded to the same chamber pressure as the .270 Win. (65,000 psi)

I have a Remington 760 pump and a Remington 700 in 30-06 and years ago had a 760 pump in .270 Win and thought it was strange I had to load the 30-06 to a lower chamber pressure. The reason is that there are to many older surplus 30-06 rifles floating around so the pressure was lowered.

Another example is factory ammunition for the .303 British is loaded to 43,000 psi and modern military ammunition was loaded to 49,000 psi. And again there are too many older Enfield rifles still being used that were made during WWII or earlier. (older softer steels and heat treating methods)