RG. I bought the Remington 660 in .308 Win. in 1971. I still have it. No it's not for sale. The only real difference between the 660 and the 600 (there are two versions of the 600)is the 660 had a bit fancier stock and 2 inches more barrel.
If you get one, be advised that sometime in the early 1980's, Remington recalled all 600's,660's, and 600 Mohawks because of a defect in the trigger mechanism that would allow the rifle to fire when taking the gun off safety. It was a free repair. There were authorized gunsmiths that did the work, so you did not have to send the rifle anywhere.
If memory serves, if the safety was partially moved foreward and he trigger pulled, and the safety then pulled back to where it should be, then the rifle would fire when taken off safety. If someone remembers for sure, pass it on.
I placed my rifle in an early H&S Precision (no aluminum bedding block) made for a short action Remington 700. It took a bit of butchery to make it fit along with a glass bedding kit.
The only other problen I've had with it, is the extractor failed about a year and a half ago. I've had a new one installed and she's fine.
The rifle has an old Weaver 3X scope on it. This is the rifle that I used to make the longest shot on game I've ever made. 427 paces. Witnessed. The deer was wounded and getting away. It was a lucky shot for me, and an unlucky shot for the deer.
Fact is, if I could find another one, I'd buy it myself.
Paul B.