416Rigby loads using Norma or Vithv. powders and woodl. 410 and 400gr. Barnes FN solids.
Has anyone developed these loads? Maybe even in a CZ550Mag. I'll be happy to hear from you.

Not using your bullets, but I have used N165 with 400gr bullets. It took quite a bit of powder, I think about 105g to make 2400fps. I've tried N160 also but don't remember how much. Please don't use the 105g off the bat because I'm not sure. Always start low and work up.

I do not use those powders but it sure takes a lot of powder to fill those Rigby cases to capacity. They work pretty well without completely filling them to the brim. Be careful and have fun.

Niels,
I haven't loaded the Woodleighs yet. But I have loaded Hornady's and Rhino's 400 grain bullets. The Hornady softs and "encapsulated" solids require 103 grains of N165 in my CZ 550 to reach 2400fps. The Rhinos, which are moly-coated, require 100 grains of N165. This is with CCI 250 primers, bullets seated to the crimping groove. I haven't yet tried the Federal 215 primers (because nobody in Paris has them in stock!) but I hear they are a better choice for accuracy in some rifles. I haven't done enough experimenting yet to come to any definitive conclusions, but it seems that the 2350fps to 2370fps loads give slightly better accuracy in my rifle. But I'm still sorting this rifle out.