It seems the 1/8 twist should be using an 80 gr bullet ?. However what seems to be available are 40-50-55 grns. Winchester makes a 64 grn but don't see it locally (rated #2 for Deer ?). Are the smaller grains likely to damage the rifle since they may be what is available. I'm not into reloading and looking for accuracy/yotes from 100-250 yds