I played around with it and you would need a BC of .770 to match the drop at 880 yards but a BC in the .8s to match the drop at 1000 yards. But when i entered in 2980 fps and kept the BC at .670 at matched both drops perfectly. I would switch your velocity to 2980 and leave the BC alone.
I'm 15 "Firearms are second only to the Constitution in importance; they are the peoples' liberty's teeth." ~George Washington
"The only advantage a light rifle has is weight, all other advantages go to the heavy rifle."
~ JE CUSTOM