When I had my Remington 770, my goal was to make it into a good rifle. However I quickly learned there was not enough good about the rifle to build around. External magazine and polymer stock, and that is where the things I liked about it ended. The feed ramps were tough and it fed horribly. The scope was too expensive at free. And overall quality was so poor, I found better fit and finish in firearms made in the Khyber pass.
Sell it and find a new project. There are plenty of other Remingtons you can build around if you are particularly brand loyal. Savage are very nice rifles to customize.