I have been using the Lee factory crimp , not the roll crimp on the dies. The case exact length is not as important on a factory crimp die as it is on a roll crimp. I have been crimping all semi-autos and hard kickers like the 300 and 338 RUM and my featherweight 7mm. I have heard talk of bullets in the magazine getting beat around and seating depth changing before you fire. It has not happened to me, but I have been crimping. If I crimp the Bergers I will need to back off the die from the recomended amount. The only reason I mentioned this above, was that I do not remember ever changing the crimp die when I was changing bullets, these are just alot softer.