I have a Dilon progressive and I load my 4570 on it whit reduce load and has every body knows there is a danger of double charging this was my solution .... on my RCBS powder checker I intaled a swicth over the rod that goes up to tell you if you have the correct amount of powder and when I double charge the rod goes up more and flick the swicth on an the swicth is connected to a buzzerd wich is screwed to the wall and beleive me when this happens I think I on the Enterprise after they sounded red alert... If the rod does not go up because I did not put powder well I am safe but I have the problem of taking out the bullet wich lodge in the barrel....up to now none of the above has happen but I feel secure with this set up...what the cost of a swicth a a buzzerd compared to a blown gun and possible injurys.... Canuck