Doe,
Here is a formula that I found and has helped me. It will give the MOA you need to dope the scope and also give the number of clicks.
First, we know that 1 MOA at 100 yards is 1 inch. 1 MOA at 200 is 2 inches, 1 MOA at 300 is 3 inches and so on. If you know the distance to your target and the drop of your bullet, you take the drop of your bullet, in inches, at a known distance divde that by the yards in MOA. That will give you MOA in come up. Then you can muliply that by 4 (if your scope is 1/4 a click) and get how many clicks come up.
Example: You have a target at 300 yards. Your bullets drops 12 inches at 300 yards. You take 12 divde it by 3, because 3 inches at 300 yards is 3 MOA. You get 4 MOA come up on your scope. Now times that by 4 and you get 16 clicks of come up on your scope because your scope has 1/4 inch clicks.
Example equation looks like this: 12 (inches of bullet drop) divde by 3 (MOA at 300 yards)gives you 4 MOA scope come up. Times 4 and number of clicks on your scope.
I always just did the guessing thing before I found this formula. I started using this last year when I would groundhog hunt. Shot a groundhog at 324 yards with my scope sighted in a 100 yards. Used the formula to dail scope in and put the crosshairs right between the eyes and that equaled one less groundhog.
I hope this helps you. If not, that's all right.
Jason gun)