Interestingly enough, I had almost that exact scenario last year, except the animal was a ram and the hunt was on day 12. It was the last day though.
My bullet was one commonly derided as a "target bullet," a 123 grain Lapua scenar. I used it because it's the most accurate bullet in the rifle I used, and bullet placement is more important than anything else.
Then you make the target right below the horns and fire.
"Only Christ is the fullness of God's revelation." Everyday Hunter