When I was shooting Bullseye, everyone used semi wadcutters unless the gun demanded full wadcutters (like my .38 Special 1911, converted and accurized by Jim Clark, Sr). Both semi and full wadcutters cut equally nice holes in the target. Semi wadcutters may feed better in some guns but I never had any problems with my Clark conversion using full wadcutters. I could not tell any difference in accuracy between the two bullet types and would go with semis every time unless there is a special reason to do otherwise.