Wrong. Go back and read his original post. He clearly states: So then I got to thinking - why not just buy an extra barrel for my '06? Then I could change out in a matter of hours, and only have about $500 invested, instead of another ~$2000 in a rifle and optic.

Replacing the barrel will only work it the replacement barrel is chambered for a round with the same base diameter or he'll end up with feeding issues which means the 338 Win Mag is a no go. And, the 9.3x62 Mauser is a much better round than the 338-06 and it has the same base diameter. Matter of fact you can make 9.3x62 brass from 30-06 brass in a pinch. So, if he wants a bigger round than the 06 on the same rifle and the same bolt, in my opinion, he is better served by the Mauser round. But that is merely my opinion however it is based on seeing the 9.3x62 used in the field an awful lot. Most Americans are unfamiliar with the round which is a shame because it is a great round and has been widely used for everything up to and including Cape Buffalo and Elephant, something the 338-06 can't claim.