Bear in mind that the stirling reputation of the 9.3 x 74 was built on 286-grain bullets, most doubles will be so-regulated, and most barrels will have a twist-rate optimised for that bullet-weight. Geoff initially made the 320-grainers for the British 360 No.2 NE, however the new PPs are a horse of a different colour.

Having said that, there is no reason not to regulate a 9.3 for either the RN or PP 320-grainers, so long as the twist-rate will permit acceptable accuracy.

I am a firm believer in big bullets myself....