The ones I know who've shot'em talk about .40 cal and up.
My good bud shot a nice 41'' this year in Zim. He was shooting 400 TSX's out of his .416 Rigby, Ruger RSM, recovering a near picture perfect expanded bullet. One shot, buff ran. They followed him (probably too soon), he got up but no one got a shot. They tracked him into thick brush, both .416's at the ready, only to find him dead. They were glad he was dead in those close quarters. Could have gotten interesting...
PH carried a .416 Rem, PF M-70, thought the RSM was a bit heavy, generally liked .416's for buff.
DF
