Can't help with that level of load, but if you really want to make it a pussycat, load 12-15 gr of unique under a 150-200 gr cast pistol bullet. My 350 Rigby, essentially same capacity as the norma, dotes on 14 gr unique under a 200 gr cast bullet. A 10 shot string was 1400 fps with an extreme spread of 10 fps. 50 yd groups are right around 1". Few things are more fun that something that has the recoil of a big 22 rf, and you can hear the bullet wack at longer ranges.
