There are several variables that can affect the bullets path. Weight of bullet, velocity, the offset between rifle bore and scope. In general terms, if you set 2" high at 100, you will be about 6" low at 300.
You are not far from Fossil Pointe Sporting Grounds, between Slidell and Decatur. They have a rifle range out to 200 yards, shooting at 200 will give you a better idea.