Nice looking rifle, Once you ditch the Bushnell you're set 
I don't think you need to switch calibers to go to 1000 yards since I was shooting my 20 inch Savage 1100 yards this summer with a Sightron 6-24x50, but if you do decide to change it up give Jerry at Mystic a call and ask him about his 6.5 Mystic. I have a buddy with one and it's definitely a shooter and can stretch way out there no problem.
I don't think you need to switch calibers to go to 1000 yards since I was shooting my 20 inch Savage 1100 yards this summer with a Sightron 6-24x50, but if you do decide to change it up give Jerry at Mystic a call and ask him about his 6.5 Mystic. I have a buddy with one and it's definitely a shooter and can stretch way out there no problem.