Originally Posted by
bigcountry
Good neck lube, and run the 308 into a 7mm die first, lube again and into the 243 die. Might have to neck turn after that. And might want to anneal depending on brass.
When going to 7mm, take out the expander ball.
pretty good description of the process.....I might add that the length of the case might require substantial trimming after this process...be sure to check and trim the brass to the responsible length.