Before you do any grinding of anything get a shoulder bump gauge of some sort so you can measure the amount of bump on the shoulder. You may not have your body die set up properly to produce the proper amount of bump. You should have your body die set up to make firm contact with the shell holder in the ram. The amount of bump is best controlled with a Redding competition shell holder set and the amount of shoulder set back should be measured with a heasdpace comparator. There is also the issue that you may have an over expanded head on your cases and your body die will not set the shoulder back because of the enlarged head diameter. Even a small base die will not set the head diameter back. Know the head diameter and know your headspace before you start brass fireform!
