Re: what to do?
A lot of factory barrels are just dogs! Can't and shouldn't expect them to shoot 'bug hole' groups. They're designed and built for the average guy/hunting situation, not for 300+yds. Winchester went thru a rough patch where quality wasn't job one. Made some good looking rifles that didn't shoot. NOT your grandpas' pre-'64 model 70. The outside of that barrel might be nice and shiny, but, the inside probably looks like it was made with a hammer and chisel. And, talk about the fit to the receiver!!!! NOW you can tell me about all those factory rifles that DO shoot tight little groups at 750+,,,,,, but I won't be listening, 'cause I know better.
"Shoots real good!": definition; it didn't blow-up in my face.