Nice choice on Rifle and caliber.

If you go with the 20X, remember, any slight shaking or movement on your part willbe noticedwhen looking down range at full 20X power.

I like the 4.5X14 better for field applications. The 6.5X20 has more critical eye relief and the mirage effect is lot worse at the higher magnification end. Might be a little better target scope, but for the combo I would pick the 4.5X14