I shoot cast out of my cutoff sporter in CBA cast bullet matches.  I have a Kraghaus long rail with a LER scope.  Slugged at .310 also, I shoot 185 gr NOE 311365 gas checked bullets over 17 grains of AA 5744, which runs around 16 fps.  I can usually group around 1" at 200 yards shooting at 5 inch CBA official targets.  Bob Wolfe (madsenshooter) graciously casts these for me, as I don't have any casting experience of my own. 

I've never tried shooting cast out of my 1898 rifle in any CMP matches however... but I know plenty of Krag shooters who do.  For my CMP Match Krag, I shoot 220 gr jacketed RN bullets.