Here is what regulates in my searcy .500:

570 Woodleigh solids
570 Woodleigh softs
570 Bridger solid
570 GS custom solid
570 TCCI solid
500 cast lead

I haven't played with the Hawk bullets enough to comment as I though I had enough to work with in the above list. So far I have only shot a bison with the rifle, but it worked great. The bison flopped over, kicked, and died before I could get the bead on him again.

Here is what did not regulate:

570 grain or lead so bullet by Custom Cast
650 grain lead bullet from Saeco mould