Step 1: Drill out the primer side
You’ll have to drill out the primer ends of both shell casings. I used a mini metal lathe with an 11/32 drill bit chucked into the tail quill. You could use a regular drill but the tricky part is finding a way to hold the shell without distorting it. Once you have both shells drilled out, you’ll have to expand the necks. Before can do this you need some measurements.