Zero change question

elarteperfecto

Private
Full Member
Minuteman
May 17, 2011
4
0
50
Argentina
Hello, Im´from Argentina and I have a .308 bolt rifle custom (FM heavy bull barrel, SS 10x42 scope, and Mauser 1909 action).
I need some help and this is the perfect place to ask.
I zero my rifle .308 at 100 meters with 25°C and I´m dead on target; I check my dope table at 600 meters and it tells me to dial 18.5 MOA (black berry gunsim.com soft); I dial my scope 18.5 MOA and hit my target (and E-siluette).
Back at home, I check the soft dope at 600 meters with a 5°C and it tells me to dial 19.5 MOA. I know that my zero will drop 3 cm (1 MOA) with 5°C aprox. The question is, how much dope would I have to dial in my scope if I don´t change my original zero, 19.5 MOA as the soft says or 20.5 MOA taking note of the zero variation?If you can give an answer about this, I will be very gratefull