I was B.C. ignorant for a long time, and I may still have a lot to learn, but now that I understand how Ballistic Coefficient relates to rifle/cartridge/bullet performance, I'm a more confident hunter because I understand how to shop for bullets for specific tasks.
Ballistic Coefficient is an arbitrary scale with which to rank a bullet's ability to resist air drag and fly efficiently. The higher it's B.C. number, the more efficient it is. And efficiency is important because it produces flatter trajectory, less wind deflection and more retained energy at all ranges.
B.C. numbers run from low, such as the .072 B.C. of Hornady's 35-grain Hollow Point XTP for the 25 Auto handgun, to high, such as Berger's .308, 230-grain Match Hybrid Target bullet with a B.C. of .743. Or super-high like the 1.070 B.C. of Barnes' TAC-LR Boat Tail .510 for the 50 BMG cartridge.
Most popular hunting bullets rate between about .300 and .500 B.C.
So what? So this: If you select the right B.C. bullet, you can markedly improve performance of nearly any rifle. Let's say you're shooting a .30-06 and want big punch to take on a moose. You can choose Hornady's 180-grain InterBond, B.C. .480, or its Round Nose with a B.C. rating of .241. A lot of old timers thought a big round nose like this hit much harder than any spire point, but check this out:
We'll shoot both bullets 2,700 fps MV, zeroed at 200 yards in a right angle 10-mph wind.
180 RN (B.C. .241)
Impact: +2.5 Energy: 2,168 Drift: 2
Impact: 0 Energy: 1,592 Drift: 7
Impact: -11 Energy: 1,148 Drift: 15.5
Impact: +2 Energy: 2,518 Drift: 1
Impact: 0 Energy: 2,176 Drift: 3.3
Impact: -8.5 Energy: 1,872 Drift: 7
Wow! The old round nose might look like a heavy hitter, but it carries 742 fewer foot-pounds of energy at 300 yards. Worse yet, it deflects more than twice as far in that 10-mph breeze while also dropping an additional 2.5 inches. Both bullets weighed the same and set off on their adventure at the same velocity. The only difference was their B.C.
If you want maximum ballistic performance from your hunting bullets, pay attention to B.C.