Good comments in the previous posts. I think you'll find this a straightforward task. Like you, I went round and round with a .357 Herrett and and 7mm TCU back in the day. Both required annealing and trimming. The 6 x 47 Remington is nowhere as troublesome.

A year or so ago, I picked up a 40 XBR in 6x47 Rem in Cabela's gun library of all places. It looks like it had been sitting in a safe for the last 40 years. It was a great deal considering the goodies that came with it. Nobody wanted it except a guy like me who had been wanting one for a long, long time. I guess I'm a dinosaur . . . .

A few thoughts: Use a good lube when you reform the cases. I use Imperial Sizing Wax. As noted by others, you simply run the .222 Mag case into a sizing die. Be sure it has a tapered expander.

My rifle came with a set of Hornady dies, and IMHO Hornady should just stick to bullets. Now I only use the die set for case forming. I quickly went to Wilson sizing and seating dies. Their website is a little quirky, but they guided me to the right parts by email. Great folks!

Brass can be hard to find, but it's out there. I see Midway has some in stock at the moment.

And lastly 6 x 47 confuses some people. Often they think 6 x 47 Lapua and have no clue about the 6 x 47 Remington.