Hi Mike

I do have Greame's book

The regulation loads they suggest with H 4831 is 103 grains , with is I presume is for the 75 grain cordite load

I could not find a cordite to nitro conversion table in the book though(Maybe I'm not looking close enough)

Using the Formula of 1.33 x 70 = 93.1 gr of H4831 - Tropical load
1.33 x70 = 99.75gr of H4831 - Normal load

Is that about what you use in you're 500/450 NE 3.25"?

Kind regards