the book by larry kelly and j.d. jones ''Hnting for Handgunners'' reveals that the truncated cone design, when of proper lead alloy, will penetrate very, Very well. the SSK bullet molds from some years ago were designed with truncated cones and they penetrated better than swc's. those truncated cone designs, and the hornady silhouette bullet in 240 gr FMJ' were used by larry kelly and others to take elephant, cape buffalo and alaskan brown bears. (see page 224 in that book for a pic' of larry kelly and his bear, and the paragraph above identifying Hornady's bullet being used to take it with one shot.....) j.d. has a chapter on bullets in that book that is very expressive of his ideas and the way his projectiles performed.
that being said, what is the game to be hunted by 300grJHP? j.d. jones advises jhp's for deer hunting, instead of his big hardcast, truncated cones. i'd expect that he's right because the jacket will cut tissue as it passes through the deer. the hardcast bullet will exhibit a non-expanding performance as it passes through the animal probably leading to a longer tracking job in many, many cases. if bones are hit and become secondary projectiles to devastate the lungs, heart, liver, etc., then the hardcast bullet is helped by those bone fragments. otherwise the JHP' performs better.
dick metcalf's go anywhere deer hunting bullet was the 210 gr' JHP' in the .44 mag' i think he and jones agree on what is necessary.