I owned a Sendero in .300WM back in 2001 and here is some of the load data that I recorded while working up loads for that rifle.
In March of that year I tried; 180gn Nosler Ballistic Tip (NBT)/once fired Rem. brass/CCI BR2/75.5gn RL22/.3400" (3shot groups).
May 2001; 180gn NBT/Rem case/Fed 210 LR/75.5gn H4831SC/.6605"
180gn NBT/Rem case/CCI BR2/76.0gn RL22/.4765"
June 2001; 168gn Speer HPBT Match/Rem case/CCI BR2/74.0gn
180gn NBT/Rem case/CCI BR2/71.0gn of IMR4350/.476"
Hope this little bit of info helps. JohnnyK.
"The only thing necessay for the triumph of evil is for good men to do nothing."