I was more looking at older 700 actions, but I’ll get what I can. An old Sako is a good idea, though. I’ll have to see what I can findI had a 300 H and H on a pre war model 70. It was just a joy to shoot , with lighter bullets, and behold. As I agesd, now 73, I sold it to a young man I thought the world of. He lives in Wyoming and just hunts everythings with it.
I cannot imagine building a custom rifle cambered in 300 H and H on a modern Remington action.
Personally I would buy a vintage Left handed Sako long action in any 30 caiber and have just the chamber rebored.
Discuss all this first with a very competent gunsmith.