I'm little late on posting this but here something current on reloading for the F-Class open rifle
Shiraz: On the .300” WSM [I run] a tight-neck .336” chamber for turned necks. Basically, I fire-form all my brass in a fire-form barrel and save the good barrels for matches. Gordy is so good that he can chamber different barrels to within .0002” in the headspace dimension. That way I can have several same-caliber barrels and can use the same brass for all those barrels. I use a .0005″ shoulder bump for my brass. I load the bullets so that the bearing surface sits above the doughnut ring.
Here is the rifle and above comment
http://bulletin.accurateshooter.com/...sm-f-open-rig/