I have never done this. How do I go about doing it. I read somehwere I could take .243 brass or .308 and turn it into .260 brass. If this is true, would you tell me how.
you simply need an expander die. you can buy them at sinclair or midway. the mandrel you'll want from sinclair will say E26
and then you put the die in your press and run the 243win case into it and when you pull it out, it will have expanded the neck to 260, which is the only difference