Their barrels are lighter. The barrels are milled down to about nothing and then built up with the carbon fibers. They are supposed to be stiffer and transfer the heat better. The carbon won't rust. However, my only experience has been with mentioned rifle, so I have never fired one.
As a side note, I spoke with Woody from Lothars- Walthers, and they have a light weight barrel coming out the first of the year. They do this by layering several types of metal together. I'm not sure of all the details, but this may also be an option.

The one I bought was very boring, it shot exactly where I was aiming. Shayne

I may go with the Tikka T3 Lite stainless. Although not a CRF, it's light weight and has some good reviews. It also is a bit less expensive.

Sevens

I have 2 buddies with Christiansen Rifles both are superb rifles, very accurate if funny looking. It might be the best way to get a M-70 light enough for your sheep hunt. -But I still think you should buy a better scope.......DJ