Rifle Scope Help Please!!?

I would want a heavier larger diameter bullet for 500 yd targets. As far as scopes go, 4x is not really enough magnification for deer at 300 yds. My son has a mil-dot SWFA 10x scope and it is quite sufficient for targets out to 440 yds and I think it would be enough magnification for 500 yds. With the mil-dots, you don't have to dink with the elevation turret if you are in a hurry to get a shot off.