RE: 30/06 vs 300 Win Mag
First off, I don't mean for this answer to be offensive. If it is, I apologize in advance, as it is not my intention.
Here goes:
If affordability is an issue, why are you converting a 270 to a 25-06, and then buying a new rifle for an elk hunt in several years that may never happen?
Options:
1. Keep the 270, as it will do anything a 25-06 will do, but better, and then buy a 30-06 if you want a 30 cal. This way, you get a new rifle.
2. Trade the 270 for a Thompson Encore in 25-06, and then buy a 30-06 or 300Mag barrel
3. (Best option) Keep the 270. If you ever hunt elk, buy some elk ammo for the 270. Take the $1200 that you'll save (re-barreling, new rifle, new scope, new rings, new bases, new ammo) and spend $100 on a really nice dinner with your lady, set $300 aside for your kid(s) education, donate $100 to wildlife conservation, donate $100 to an animal shelter, donate $100 to the non-profit of your choice, and invest $500 in a good, 5-star mutual fund. This will make your lady happy, your kids happy, animals happy, other people happy, and your wallet happy.