I have killed elk with a 300 Wby, sadly those days are over. In the area where I hunt, grizzly's rule the woods. I consider the 300 Wby borderline on deterring an bear attack. If I hunt elk now, I take a 358 Norma. If I ever draw a tag in the lowlands (where there is a herd of about 35-40 elk), I will be comfortable taking my 300 Wby again. However - nothing says "watch my back while I quarter this" like a 250gr 358 bullet.
Some is Good---More is Better----Too Much is Just Right
