I had a .500 NE built by Hamilton Bowen . It was a great shooter and he did great work on it. It was his opinion at the time that a full .577 (750 grain bullet) was too much for the #1 action. I know that he built some " black powder/light nitro .577" on #1 actions !!! I took mine to Africa once and it worked beautiful !!!! I saw my gun a couple of weeks ago for sale at Champlin's if anyone is interested ? Not sure what they want for it. I still own a 450/400 3" they built for me , in my humble opinion this is a much better choice for the #1 action (jmo).
Robert