I've tried loading .535 ball and could not hardly get it done. I can remember one afternoon a friend and I were shooting the new .535 ball we casted. A real comedy routine out there, we set them and then could not get them down the barrel, so we stuck a heavy range rod against them and had to ram the rod against a tree to get the ball set enough to load on the powder charge because neither of us remembered a ball puller. That was the first .535 experience I had. I still have the LEE mold in my collection... they work great out of my wrist rocket sling shot...