Ovny-

Years ago I shot with a bunch of guys who'd keep history books for each and every one of their rifles.
Every rifle had a book.
Every shot was recorded:
-Bullet/Brass/Primer/Powder/Velocity
-Sight Picture/Hold/Call/Point of Impact
-Altitude/Visibility/Temperature(estimated AND actual)/Humidity(est&act)
-Range(est&act)/Angle(est&act)/Wind(est&act)
-Position/EtCetera

The books exist as a complete living history of the rifles, and there's a lot to learn from each/all of the lists of data.

I think you would likely do well with such a record of your high-power long-range rifle -- or any rifle you have.
You will have the chance to get the most from every shot you fire, and with that information you'll be able to make the most from any opportunity you get in the field.

Cheers
Tinker