I've been tinkering a bit.. I have noticed with full bore slugs that they have a tendency to engrave the rifling unevenly... It seems to me, the more plastic I add to the engraving surface of the slug, the better it centers in the bore rifling.. I'm not sure why that is. But scores of recovered slugs tell the tale.. So I hope to test this theory within the next few days.. Here are a few of my test subjects.. The solid orange slugs are 530 grains and the attached base wad slugs are 450 grains.. Hopefully we will have a winner..d