SmallCaliberCentral

I loaded some 300 win mag with 150gr. bullets and 76.gr. IMR 4350
my book says this is max load and most accurate my is 1980 issue
IMR web site says max load is 74gr. I had the 76gr load hilited
in book with it shooting at .327 moa. Is the new powder hotter are
somthing or is it a lieabilty issue? do guys have any idea's or what
does your book say?

Did you work up to this load?

EVERY rifle/pistol is just a bit different. Different lots brass/powder/primer/bullet/etc/etc provide different pressure in YOUR rifle.

Try here for the current info:

http://data.hodgdon.com/main_menu.asp

150 GR. SIE SP IMR IMR 4350 .308" 3.340" 69.0 3003 50,100 PSI 74.0 3254 61,500 PSI

Another thing could be is the difference in lots of powder when they were tested. Its not uncommon to find minute differences across different lots of powder.

Its also a fairly safe asumption that the powder and bullet companies publish there max loads less than the actual safe max load. But note, the word asumption.

You need to work up and if its a ball powder or any one suspectible to temp changes you need to take that into account as well. As always, go for the most accurate load.

HTH

bret1963.............Don't think its a max load but it shoots in two 300win mag that my buddy and I own!!! H-1000/81.3/150 Berger.
If you have that powder and bullet on your shelf give it a try.
Later
Ray P.