At the time I owned my .340WBY,1977-1981, the Nosler partition was the most reliable bullet availble. I used the 250 gr loaded to 2850fps and never felt the need for anything better. I still favor Nosler partitions for all North American big game from .270Win to .375 H&H but they are not really needed for the .300 Savage and the slower velocities of the 9.3x57 and 9.3x62.
If I were to invest in a classic custom rifle I would want a classic chambering. If I bought a rifle specifically for hunting in BC or Alaska I would consider the .33Nosler,the RUM or the Lapua. A friend of mine has a .338/.378 WBY accumark with Nightforce scope. It has a 28" barrel including muzzle brake. The ammo, which he reloads, costs new,over $200 bucks a box and is a special order. The rifle is absolutely no fun to shoot. More brutal than a .416 Rigby CZ 550 or a Browning High-Power .458 Win. He cut his brow on three occasions, one ruining an expensive hunt and requiring medical attention. The local range will not allow him to use it on weekends or times when the place is crowded.His hunting partners last one hunt but he has bragging rights when it comes to ballistics.