It pretty well just has to be the difference in loads. An 1898 (notably higher) front sight would probably go a long way to ease the problem. Are you going to hunt - where you need to know where the bullet will impact, or just 'punching paper' for fun?
If the latter, an easy solution - very familiar to .45-70 'trapdoor' shooters - is to use two bulls, one above the other - aim at the lower and adjust the vertical spacing until your groups land in the center of the upper. That way, when you show your friends a nice tight group it isn't just in the white backer...