Rifleman,
There is nothing wrong with Wal Mart specials. I shop there myself.
HOWEVER, and (this is a big however), according to a friend that is "in the know" in the retail department store industry, Wal Mart purchases it's discounted guns from major manufacturers because they carry the plainer wood and metal finishes.
In other words, that M70 Winchester that you are interested in is not what you might find at a retail sporting goods chain store for a higher price. It's discounted because it's plainer and intended for the less discriminating mass consumer. I got burned in buying a Ruger M77 in 7mm Remington Magnum several years ago, and discovered (after purchase) that the "bargain" price was because Ruger ran a batch of receivers through hot bluing and they came out not dark blue-black, but dark purple-black! Yep, the bluing salts solution was overheated. The discounted price was some 30% below MSRP.
Further, the Winchester Short Magnums may be a temperary flash-in-the-pan for popularity. They were intended to duplicate full-sized cartridge ballistics in a shorter, larger diameter cartridge case. That means proprietary cases with limited availability. That spells limited popularity and almost certain obsolescence in terms of ammo and component availability in a few years. Look at all the obsolete cartridges of the 20th century, and most of them started out that way.
I'd probably NOT get interested in that deal unless it is clearly a LARGE discount over what a comparable rifle in a more standard caliber would cost. A more standard chambering means retaining it's value better.
HTH
John