Farshot,
A friend of mine had nothing but trouble getting bullets for his 470 NE double. Very frustrated, he solved the problem quite nicely by purchasing a new bullet mold that RCBS brought out a few years ago.
He now casts all the bullets he wants from wheelweights, and loads them to almost 2000 fps with IMR 3031. Uses them for practice,plinking and hunting over here and only loads with the much more expensive jacketed bullets when he goes to Africa.
Just something for you to consider.
Ted