Yeah Hey that's cool I get it I understand all the lingo I was just making Is a point That not everyone's Gun Smith I'm not one but my grandfather Was. speaking in layman's terms makes more sense to more people And I appreciate what you have to say And all your easy learning tools God blessFair enough. Here's some simple info for you about this subject.
BC is a measurement, against a standard projectile, for how well a bullet can over come air resistance.
There are many standard projectiles, for various bullet shapes; G1, G5, G7, etc.
What most reloaders know/see, are single G1 BC numbers. However when shooting most match type bullets, such as your tipped boat tail; those aren't a good match against the standard G1 projectile. So for such bullets, there are actually several G1 ratings, depending upon speed. If you go to Sierra bullets website, they actually list the 'steps', which will give you an idea of how that works.
Your proposed bullet, is better served by using the G7 coefficient, until you drop below the transonic velocity range. At that point, the lowest G1 becomes a better description of how the bullet flies.
A really easy way to see/track/learn this, is from one of the regularly updated ballistic calculators. Such as Hornady's 4DOF calculator, or the Shooter app by Sean Kennedy.
Best of luck in your efforts. 🙂