The point he's making is that for your first truly LR rifle, you'll be better served by a 6.5 or 7mm than a .300WM. The external ballistics of the 6.5 and 7mm bullets give you an enormous bang for your buck as far as recoil, powder consumption, and bullet price goes. I would look at the .260 or 6.5 Creedmoor if you are interested in low cost, low recoil, high user friendliness, and great accuracy and ballistic potential. The next step up would be the 7mm Rem Mag, which gives equal and even superior ballistic performance to the .300WM, but with less recoil and cheaper bullets.
Either choice will be something that you will enjoy practicing with much more than with a .300WM, and therefore you WILL practice more in the end. If you practice more and enjoy shooting the rifle more because of the relatively gentle recoil, you will quickly be better able to place the bullet where you want it at long range, and that is far more lethal than a slightly larger bullet from the .300WM, if placed not quite as well. After all is said and done, you will be a more deadly LR hunter with a .260, 6.5 Creed, or 7RM, than you would be with a .300WM, unless you've put thousands of rounds down range from the .300 to learn the rifle and condition yourself to place your shots with precision, despite the unpleasant recoil.
And it wasn't a smart ass reply. I was serious.
