ok i think im about to take over my dad's 300 win mag HART. its a long rage rifle so ima put it to use. i know he will never really end up shootin it.i know hes gonna give it to me soon anyway. it has a leupold 30mm tube 10x scope. and i have a nkon 30mm tube 10x power scope. thinkin about gettin turrets for one of the 2 and put on there. but how do i get a drop chart of whatever i need for the turrets? so i know how many clicks i need for what range. kinda new to the long range thing. out past 300 yards. im not gonna be shoot no further then 550 yards. the nikon has the bdc reticale in it but not sure if i waanted to use that or not. any info will help please thanks! need help gettin started!!!