Piro,
Welcome to the club here.
You really are better to just believe in the best numbers possible. Sight your rifle in for 50 yards.
Then check your drop (or height above the bulls eye at 100 yards and possibly 200 yards) by holding dead on, with 3-5 shot groups at 100 yards, 200 yards and 300 yards.
I wish i had a .243 to play around with!