You know, in reality, this guy is shooting a 308, if he simply sights in at 200y he can aim dead center of deer shoulder and drop the bullet in the dead zone out to 300y, and then some.
But, IF you want to know, and or place the bullet exactly where you want or need it, your going to have to do some math, like it or not, that's the way it is!
Also, your going to have to do shoots at the distances you intend to work, and under a variety of conditions, all the while compiling detailed notes for future reference.
The lab coat formulas we offered do work, but they where only a small part of the whole equation, we did not figure in any atmospheric variations, wind, inclination or ammunition variations data.
Now, do you need, or have to do all this to bust a 9 point out of your lucky stand....no, you don't! Your 308 is flat enough to do the deed out to 300y without too much computations, but your still going to have to some figuring in that big head of yours! lol hehehehe