I'm guessing it's a 270? I just finished testing some 165 Gr Matrix out of my 270 WSM, penetration was ~3" of water (milk carton) followed by about ~9" into wet newspaper. I haven't cleaned & weighed the bullets, but none of them blew up, they all penetrated similarly, no core separation and near perfect mushrooms @ 25 yards with velocities ranging from 2975 to about 2500 to simulate close & LR shots. Shoot with confidence using these from 0 to 1000 yards on anything with 4 legs. I'll post results when I get through them.
Also, the entrance into the newspaper stack was about the size of a baseball (after ~3" of water in a milk carton), so don't be worried about these penciling. I know these kinds of results are not empirical, nor do they represent permanent wound cavities, but I was still impressed. There were bullet fragments found everywhere starting from about the 3" mark of newspaper (6" total penetration). I wish I would've got a picture of the newspaper stack after 6 shots into it, wowza.