Any ideas? I loaded some 410 slugs by: used Speer .323 8mm 150 gr jsp bullets because they fit in the wad seemingly perfect. Used 16 gr H110 powder. I originally wanted to use 357 dia bullets but found they were too big dia for the wad. The 8mm bullets set in the cup of the wad just snug and when pushed in the shell it was just enough pressure that the bullet could not be shaken out. I thought it was perfect, no criimp, open front. I knew the powder charge was for 4 double ought buckshot, weighing about 212 grs, heavier than my bullet, but then the firing. first bullet, at ten feet into a 1x4 board, hit perfectly sideways, dented about 3/16". bounced back about 3 feet. second shot hit straight, stuck in the board about 1/2". Guessing it was shooting about 400-500fps. Did the lack of crimp make that kind of difference or was the powder charge that low?