OK fellahin,

257 AR is a good round for these parts up to 500 yards if you can do it. Mine is zeroed at 300 with abt 24 inch drop at 500.

Game is at best red deer to dingo (realisable body mass as a PoA at extreme range).

An 87 grain Speer load of 51 gn of 4350 WAS 3750fps with no pressure signs so in the interests of sanity and OHS I backed off to 3500.

Otherwise I would endorse a 6.5 x 55 as the best ARR up to 500KG meat. (a mate took a Kudu with 56" with a 6.5 Fraser Brummy retail model)