David Tubbs is getting a shipment of 6xc Norma brass in next week.
David Tubb Accuracy & Precision Gun Parts
It will probably go fast Call and get some ordered.
I have the same problem with neck and full length bushing dies. Adjust so the bushing does not size most of the neck. I only size about 1/2 the neck and can keep runout about 1/2 thousands.
After reading this thread i checked my loaded rounds in 6xc and 338 edge that are seating once and found very little variance in CBTO,1 to 2 thousands average and a couple with 3 thousands. I think it just variance in the bullet itself. I am sure there is something to this topic but i am not...
Probably about 40 grs. depending on your barrel. I am using Broughton barrels on both of my 6 xc's and i am able to use more powder without pressure than most people's guns in 6xc. The 105 hybrid has been consistent for me than the 115's.
I use 35 Whelen brass. Neck it down a little at a time until the bolt closes with a little resistant to create a false shoulder. I like the false shoulder method better than jamming a bullet into the lands. I fireformed with pistol powder and cream of wheat.