does anyone know where i can get a priming tool that will fit a 577 nitro? thanks

Gerryb;

I've not see a hand priming tool for boxer primers for that large of a case. There is the rare one for berdan primers that came in cased sets. The RCBS bench priming tool will do the boxer cases as it comes and can be made to do berdan cases with a modified shell holder and seating punch. If you don't already have dies get a tight hold on your wallet if you order them from RCBS, IIRC they wanted $600.00 when I priced them. I see you're wanting cast bullets for the 577 also, which weight 650 or 750 grain?
I don't know of a comercial source for the bullets, perhaps someone else does.