DOPE=Data On Previous Engagements. Your DOPE is going to be specific to your rifle/scope/ammo and can vary with a multitude of factors. The ballistic calculators mentioned earlier will get you close (close being a relative term at 1000yds) but you'll actually have to put rounds on target to know how your system behaves.
Out to 400 yards it should be a simple matter of compensating for wind and bullet drop, much past that and things start to get complicated.
I don't collect guns, I accumulate them.