I've got a nice 225646GC mold I use with my 223 Remington (CZ-527) that I've been getting great accuracy with. I decided to try a little hotter load, and when I tested it I couldn't get a consistent group-- not two shots in a row on an 8" target at 100 yards. I couldn't even get on paper consistently to zero the load. After much puzzling I finally remembered to calculate the RPM-- and discovered I was Waaaaaay over the RPM threshhold for cast. I forgot to pay attention to the advice from the experts here on Castboolits. Live and learn.