I use H4350 with a 180gr RN Hornady and push it about 2100fps. They work pretty well and I can keep it all in the black at 200 yards fairly easy. On a good day more are in the 10 ring than not. Recoil is definitely lighter than the factory Krag ammo I have tried so hopefully it is kind to the old rifle.
I have just started testing H4831SC too and it is promising but so far I haven't outperformed the H4350.
I agree with the other posters that say flat base bullets, slower powder and the 30" barrel agree with each other.