Every true test I' ve ever seen (done on large animal carcass' and wet magazines stacked in boxes) showed quality 180s to out penetrate 200s in practically every 30 cal known to exist. A 180 Xbullet is as fine a elk round as there is available. Despite what the manuals say, I seriously doubt you would actually get a 200grainer over 3k fps with a 300Wby (a 30/378 Wby easy, but not a standard 300 Wby).

Why hamstring your 300Wby by shooting 200+s from it? The round is such a fine round, plenty of power and longrange ability, but that is hampered upon with heavy bullets. The old days before bullets like FailSafes, Xbullets, Swift A-frames, Trophy bonded etc. mandated the use for such heavy bullets when fired at big animals at higher velocities and still have them hold together. But since the " tough" bullets have been perfected and slower powders to drive them fast have been perfected over the years, I just dont see any need for a 30cal over 180 anymore.

Good luck and save some elksteaks for me,
RA