First off let me just say, put a muzzlebrake on that .300 Win Mag and it will be like shooting a 30-30 or .243 depending on the load and the brake you use. Second off, ER Shaw use to be fairly local to me and back in the day people said they made pretty good barrels. I don't like to say negative things, but the consensus now is that there's better options for barrels and rifles. If I had a $1500 I would buy a factory rifle like a Savage or Remington and see how well it shoots and get used to it. Then upgrade the shortcomings of it. A nice stock is $250-400, trigger upgrade is $150, barrel is $300-350.
If you buy a Remington, you can get some models, like the 700 Long Range, that come from the factory with a nice B&C stock. The rifle brand new is about $700. You can upgrade the trigger ($150) and have a gunsmith install a barrel and muzzlebrake and have around $700-800 in it. You'll be right around your $1500 budget but have a tack driving rifle with a premium match grade barrel. Just my thoughts.