I Got the first data to reload the 300 WSM off the internet about 2004 to feed a Kimber Montana. My Best Load, Win. Brass, WLRM Primer, 65.0 Gr. (Sixty Five) IMR 4350 Powder and 180 Gr. Sierra MK, This was max for Speer Data at that time, good velocity out of a 24" Barrel and 9/16" to 1" groups. Worked up same load for 180 Gr. Hornady, and 180 Gr. Nosler Partition. Nosler not quite as good accuracy but great terminal performance on Elk and Caribou. I have some H4350 but I have not worked up a load with it. I have Tried IMR 4831 but did not get the wanted velocity with 180 Gr. Bullets. It may work great with 190 or 200 gr. Bullets. Good Luck on finding a load.