long range rifle recommendation

I'm shooting a browning BAR mark II 30-06, 155 grain Hornady BT HP with 51.0 grains of H4350, I have a 4-12 Leaupold. I zerod my rifle at 300 yards and my bottom dot is 400 yards. How much would my bullet drop at 500 yards? Am I even still in the scope?

Hi looking for some advice; I have a S&W AR15 I use for plinking usually at 100 yards but I'm thinking of getting something for longer ranges - 300 to 400 yards. Been thinking of either a Savage #12 Long Range or a Mossberg LR - both in 6.5 Creedmore. does anyone have a preference? Also I think...