QL suggests. Case capacity of 107g for the 416 and 113.3g for the Jeffrey... the rest is maths.

Again, quoting from QL, 72g H 4350 should produce 2128mv in the 416 and 2073mv for the Jeffrey (assuming .416 Hornady DGS x 400g projectiles are used in both calculations).

N.B. Figures offered only by way of comparison.... powder burn factor not recalibrated !