Vihtavuori and American powders have recently become available to South Africans, albeit at considerably higher prices than our own SA powders.
Our Somchem powders have become unreliable in availability.
If you have it, please supply a load for the 300 WSM with Vihtavuori and also IMR 4350, which I understand is the virtual equivalent of our S365 for the Barnex TSX 165 grain.
Mine is a brand new Browning X Bolt and so additional information like overall length will also be appreciated.

People use .300 WSM data for .300 H&H. Based on that, I'd try Somchem's load using 168 gr PMP SP. [61.2 grain "start" to 68 grains "max", see p. 42 (1997).] Substituting your 165-grain Barnes TSX for the 168-grain Barnes "X"on p. 52, Barnes based data shows 59.4 grains SR 365 "start" to 66.0 grains "max" for SR 365. Try IMR 4350 starting at 60 grains and work up? Lekker dag.

Thanks for the advice, BNagel.

Almost every Reloading book in existence has data for the 300 H&H..Its very popular in African, I know many PHs that still shoot it. I love the old 300 H&H, and loaded to max its gets right up there..In many cases its under loaded for some reason, maybe some think because its old the won't take the pressure, not true It will walk with the wby..

My go-to load for 300WSM was a 165 grain Hornady IL over 66 grains of IMR4350. This was a full power load and I would advise working up to your own safe charge weight in your rifle.