Sir your Feather weight M70 is a some what rare variation of them. In Excellent condition, $2,200 Very good $1750, good $1,400. The 243 caliber is the most common feather weight caliber.
As was suggested, properly clean the barrel and shot it, it may very well surpise you. Let the barrel cool between shot strings as this is a very light barrel that heats up fast. But the sure carry nice with out the extra weight. Mine in 264 Win mag heats the barrel to very hot in 5 shots! Did I say they carry nice???
It's a keeper in most folks eyes, I think...
Best regards, Kirk