I've used the 120 gr. XBT's, the 140 gr. and 160 Nosler Partitions in cartriages like the 7X57, the .280 and the 7mm RM for many years.
I think I'd just do a good load with a temp insensitive powder like the Hodgden's or the Ramshot line with a 160 gr. NP. It should be very close to the factory ammo with it and the Swift A-Frame bullet. Can't imagine anything much more practical. E