Sir,
I will take a slightly different way to answer your questions.
First, purchase a reliable ballistic application for your iPhone, android, etc etc...Learn it and use it every time you shoot regardless of range. Most of these apps are amazingly close in their predictions and will eliminate the guess work about how much to come up or hold over.
Shooting at distance requires good optics and preferably a scope with turrets that eliminate the guess work of how much to hold over.
Next insure you can shoot well at 100yds before moving further out. Any problems with shooting technique are magnified as you shoot farther.
Study wind..trajectory is science, wind calls are a combination of experience and black magic and even at 300 a switching wind can drive you crazy.
Either of the calibers you have are certainly capable at 300yds and beyond with multiple bullet weights provided your rifles are capable of delivering consistent accuracy with the bullets you have chosen.
Bill
