You can buy a NEW Model 70 for what it cost for a Montana action.
You can buy a used, beat up Model 70 for a heck of a lot less. In fact you can build a rifle on a used Model 70 action for what you'd pay for a Montana action.
We'll discard the cost of putting it together since both actions will require that cost.
Action $350 ( taken from a used rifle, less if you find a beat up rifle. Action will still be sound)
Model 70 Marksman Stock (Select) $127
Barrel $200 ( good quality Douglas Prem. or Shilan Stainless)
That's $677, or about 100 bucks less then the Montain Action.
A Montana Action with the same barrel and stock would be about $1077.
What makes the accurate rifle is the care in how its put together.
The Model 70 300 WM I posted in the above picture (earlier post) cost me about $235. $40 for the action (235/6), $80 for the Bishop Stock and $100 for the unturned barrel blank. I did the work my self. Including making the hand stop rail. Granted that was a while ago, but the $677 number is fair for todays prices.
I'm not one that believes one has to a multi thousand dollar rifle to be accurate.
One of the best shooting guns I have is my wife's 243. I used one of my $40 actions, a $112 douglas barrel, and the stock is a Wincheter pull off I bought new from a gun smith for $50. It was off a new rifle someone wanted replaced with one of those plastic stocks. That's just a hair over $200 bucks.
Its the care you take putting it together that counts, not how many dollars you spend.
You could put the extra money in rounds down range and be better off.
If you don't have to have a Winchester Action (I'm cursed for saying that) you can buy a Mauser 98 action from shotgun news for less then 100 bucks and make a dern nice shooter.
Just noticed I didn't post the picture of my 1000 yard rifle. Here it is.