After knocking the old primers out I use the Lee chamfer tool
to buzz out the crimp. It slips neatly on top of a magnetic nut driver drill bit (with small piece of masking tape between the chamfer tool and bit to make it snug up). It looks like it came that way from the factory and works flawlessly.
Once complete switch to primer correction tool
and use drill to buzz out primer pocket. I have been advised to use this tool with the drill on low speed, so as not to cut too deep.