I use a load which drives 220's at 2335 in my 30/40 (not a Krag rifle). The elk I shot with this hit the ground so hard he bounced! I think 220's are a good choice if one likes the reliable performance of heavy round nose bullets. Just like 160's in a 6.5, they expand reliably and penetrate well.
Starting out at 2300-2400 fps, they shoot flat enough to make 300 yard shots possible if necessary but they are best at 200 and under. GD