I have been using an M die for years after sizing and trimming with the RT 1200. It puts a slight flare for flat based bullets and gets rid of the slight inside burr. I am on my 3rd AR barrel with no problems in 223 and second barrel in 308. The M-die can be used in station 5 in the 650 when trimming or put in station 1 the second time thru using the 550. I prefer to use a universal decapper in station 1 to remove any grit in the flash hole if I tumbled them after sizing. The lee factory crimp die removes the flare and gets rid of the outside burr too.
