It's been said by some "experts" that the LCD's don't provide the uniformity/flexibility of a bushing bump die. Maybe in Benchrest competition this is true. I use LCD with body die and can find no advantage to the bushing bump dies that I've also tried with same cartridge in a tight neck chamber. However, I find that jamming .010" to .015" requires me to reduce the diameter of the LCD's mandrel to maintain enough neck tension to prevent bullet set-back upon chambering. The amount of set-back is dependent on ogive shape in my testing. The "darts" won't set-back as far as a more rounded ogive.