You won't get any gripes from me. Heck, I swage jacketed bullets for my 9.3x57's out of 9mm NATO and 7.62x25 empty brass filled with wheelweight metal!!

However, I have an honest question:

Recognizing that this project must originate from some need or curiousity, what is it?

Is there some performance superiority of a 720 gr bullet over a 500?

Seriously, I am wondering, as I can conceive of a whole host of good reasons for a 500 and maybe even 600, but the length of the 720 makes me wonder about case capacity, etc.

More info please!

By the way, I remember reading an article by Jack Lott {G&A??} back in the '70's about a "friend" of his who had a .458 Lott and a .458 Winchester in Thailand. Used cast bullets on their buffalo there. They worked.