I imagine you'd know, Nigel, but compared with the NE version it would have to be better unless the extra mass of the NE rifle nullifies all distinction. Using Nitro for black loads would drop the ejecta load by about 100 grains, too. While not experienced in such big calibres myself, 650 grains at 1650fps from a 12-pound rifle sounds like a gentler proposition than 500 grains at 2050-odd from an eight-pound 458.

Cheers
- Paul