KcTbear,
I'll give you a starting point on loads for your .300 win mag. The first powder to start with is REL 22. That's probably, of course it's debatable, THE powder for a .300 win mag and 180 grain bullets. 75 to 76 grains is most often THE most accurate load based on my endless reading on the subject.
My best load, in MY rifle, has been 75.5 grains with a 180 gr Nosler Partition, WW brass that's PFLR sized to fit my chamber and a COAL of 3.360".
You'll get many other opinions about THE load for a .300 win mag, but this is as close as it gets to a go to load.
