BALLISTIC CO-EFFICIENT OF H-G BULLETS

The number one question we field from our customers is, “What are your bullet B.C. Numbers.” For those of you who wish for a number to plug into your ballistic programs a list of the numbers on our current jacketed bullets follows. We will add to these as our product line expands.

B.C.

Now the cautionary part; We don't generally put much stock in B.C. numbers. Ours or anyone else's. This is largely because they are at their best misleading. Often they are outright wrong. And rarely are they anything but a "ball park" figure that will maybe get you close to projections. This is because a B.C number is never fixed. Every conceivable variable affects it. Velocity, humidity, elevation, barrel wear, twist rate, wind, and about a gazillion other elements will cause a B.C number to vary high or low from those that are published.

We use a computer program to calculate our numbers. Our program uses a long time standard of: 60 degrees F, 30" barometric pressure, and 2/3 saturation of moisture at sea level, as the fixed external variables. If we keep everything the same but jump up to 2000 feet above sea level, the B.C. number will be higher. Change the humidity and temp, and the number changes again. We also have to plug in a velocity number for the system to work with. We try to pick a velocity that is sort of middle-of-the-road for the caliber. Remember; as velocity increases B.C. decreases (generally) And as your velocity drops down range, the B.C will increase.

What I'm getting at is that our published B.C. (In fact ALL published B.C.'s) should only be regarded as a broad guideline, and should be taken with a large grain of salt. I'm not looking to throw stones at anyone in particular, but it is a pretty standard practice to try and make a bullet B.C. look as good as possible for marketing purposes. A lot of shooters are absolutely obsessed with B.C.. In fact, for far too many it is one of the primary, if not the primary criteria they look at when selecting a bullet. (A Sometimes tragic mistake that I'll cover in much greater detail in another article.) Bullet makers big and small know this all too well and they will sometimes go to great lengths to gild-the lily so to say.

One maker I know of wanted a particular bullet to outshine every other bullet of similar weight and caliber . When he calculated his B.C. he plugged in a velocity about a thousand feet or so slower than any of the more common cartridges for this bullet would produce. Then he increased the elevation in the program until he reached a B.C. number far above anything else on the market. When I tested that bullet from a really fast stepping cartridge at about 1200 feet above sea level I got a result about .040 lower than his published data. Not that he outright lied. He just used a best case scenario.

Our Friend above is by no means alone. I've had plenty of opportunity to test bullets from manufacturers both large and small, and very rarely do the live up to the numbers. Although to be fair, on a number of occasions I've had bullets exceed the published numbers - A couple of times by a wide margin! Which is the crux of this tome. The only real way to get a really close B.C. number is to test your bullet choice, in your rifle, under your conditions. The number you get won't be the same tomorrow, or next week, but it will probably be closer over all than what we provide you in a generic guideline. All you need to do is set a chronograph up at the muzzle, and another at 100 yards, and shoot over them at the same time. Record both velocities and plug them into any one of a number of ballistic programs. (I've used the free pointblank software for this with complete satisfaction) And you will have the B.C. of your bullet, in your gun, on that day.

That said, you shouldn't really put a lot of stock in the importance of B.C. anyway. I've had customers literally freak out over the difference between a bullet of .240 B.C, and one of .245! Really? In, let's say a 22-250 shooting a 55 gr bullet at 3600 fps, that translated to something around .20" less bullet drop, and .48" less wind drift at 400 yards! WOW!!!!! It would take some kind of seriously accurate rifles, and a bone fide superman on the trigger to take advantage of that! And yet, people worry about such minutia every day . . .

I say relax, and don't worry so much about squeezing every last micro inch of bullet drop and wind bucking ability out of your rifle. Select a bullet that will give you the performance and accuracy you need on target. Figure out the real world trajectory with your guns and loads, and just practice hitting things with it.