As a lifelong machinist/mechanic when I first encountered crimped primer pockets I immediately thought of a countersink. I have removed the crimps from thousands of ex-military brass with a simple twist taking about 1/2 second (9mm, 45 ACP, 30-06 and 7.62x51, and a rare 38 Special). I have never had any problems with my method and one would have to try pretty hard to remove too much metal. Inexpensive, simple and found at most hardware stores. I had/have 60 degree countersinks in my toolbox and they work quite well...
McMaster-Carr
As a lifelong machinist/mechanic when I first encountered crimped primer pockets I immediately thought of a countersink. I have removed the crimps from thousands of ex-military brass with a simple twist taking about 1/2 second (9mm, 45 ACP, 30-06 and 7.62x51, and a rare 38 Special). I have never had any problems with my method and one would have to try pretty hard to remove too much metal. Inexpensive, simple and found at most hardware stores. I had/have 60 degree countersinks in my toolbox and they work quite well...
McMaster-Carr
Would you post a picture of what you use and will it work for 223/556?