As mentioned the bigs cats chest is more heavily built than many think. This is what cost the Lordling his life when he shot one with the new wonder 280 Ross and the lighter construction bullet. The bullet made a very nasty and possibly fatal eventually wound tot eh Lions chest but did not reach the vitals and the Lion hauled up down mauled him than chewed on his head.
Will have to see if I can find the report as it was along time ago that I read it now which is why I cannot recall the name
. The too lightly constructed bullet hitting at a velocity of around 3000 fps fragmented leaving a large shallow wound that just made the Lion MAD at the time.
Hence I would chose a bullet designed for such game and not trust what was designed for paper punching. As mentioned Alaska, Partition, H Mantle or something along those lines.