Was it the 7mm wsm
article on 6mmbr.com?
I do this, but very slightly. After you deprime and run the primer uniformer with the drill to get rid of the carbon you will usually remove some brass so this removes the previous chamfer. I do this before every loading, but only slightly. I have found that after a couple reloads a primer hole if left uncleaned will have build up in it so I use the flash hole deburring tool and just stick it in the hole and twist a couple times to make the hole perfectly round again and add a slight chamfer.