I am looking at a M70, stainless, synthetic, Winchester( US Repeating Arms ). I would like to build a long range rifle and have so far not found anyone with much info. . Advice, thoughts on this caliber or other calibers appreciated.
This round is equivalent to the 300 WM but fits the short action.

Being a Die-Hard 300 WM dude, I have some thoughts.

1) The Round is going to generate insane chamber pressures in that squatty little case. I'm sure it has some heavy walls, but whatever.
God has already spoken when it comes to messing with good chamberings.
Every dude who has ever seen a photo of a blown-up .40 S&W can probably figure that was just gods punishment for messing with the 10MM.

2) When the round first comes out, there is going to be very limited ammo availability.
Bad News.
And for what?
Why not the standard .300 WM??
A shorter Bolt throw???

Way I see it, if you really are in a situation where the difference between a long-action and a short action is going to make a practical difference, you should be using a semi-auto in the first place.
If you are at a distance far enough away from your target to utilize the Juice of the .30 Mags, a long-action or a short-action isna't going to make a difference.
So there is no real reason to get this newer round over the proven .300 WM in the first place.

My .02 cents.

McUZI, Deputy Ambassader to the Secratery of Foriegn Relations of France