SXS:

Welcome to the club.

I don't have any loads for the 500/450, but I'm sure someone on here does.

Are you shooting new Kynoch rounds?

If this forum turns up dry, you may consider sending the rifle to superior ammo and let them work up a load for you. GREAT, HONEST and RELIABLE people up there in SD. Will probably cost a few bucks, but will be cheaper in the long run.

Oh, are you in the States? What DR do you have?