Here is one from up here in Canuckistan for sale, no rib though..... 600's and 660's are sweet handy rifles!
Remington 660 6.5 rem mag
I have for sale a very nice vintage remington model 660 in the remington 6.5 magnum, the 660 is the 20 ich barrel with no vented rib, this gun is in very good condition, comes with original sights, there is some minor wear, small scratch on the butt stock can be seen in the photo, blueing is very good. $700.00 shipped
Remington Made a model 673 that was copied after the 600 except for the bolt handel
(It is like the 700) with a nice laminated stock and a vented rib that is a beautiful little rifle.
The action is like the model 7 and came in 243,260,7/08,308,6.5 rem mag,7mm WSM and
300 SAUM if you can still find one.
If you remember the 350 REM MAG that is what they look like.
Check Cabelas gun library They had a number of them for sale around 1000
Thanks I have talked to them but am having trouble wrestling with the $1000 and $1100 tag right now. They bought a large old collection and had some 223's I wish I had gotten in on though.