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The shape also has an effect on BC, sometimes quite large.
For example, the .30-06 M2 Ball bullet is nominally 150 grains, and goes subsonic (thus getting whipped about by wind a lot) somewhere between 700 an 800 yards, IIRC. But the 7.62 NATO, by adding a boattail and using a secant ogive (specific front-end shape that looks less aerodynamic than the gentle curve of the M2), gets at least an extra hundred yards, with measurably less wind deflection before the dreaded subsonic zone. I think that's even with a MV of 75 fps less...don't have those military data sheets handy...
And it weighs 147 grains, nominal. Okay, it's only 1/30th less, but there is a difference.
The VLD (very low drag) design of the newer Sierra 155-gr Palma Matchking makes it carry downrange as well as design of the revered 1962 or whatever year it was introduced 168-gr Matchking. But since it can be launched faster, the 155-gr carries all the way out to 1,000 yards from a .308. The 168 needs a .30-06 or better to be used at 1,000 yds.
The decimal value of the BC is supposed to be how well the actual velocity loss compares to some mathematical "ideal" shape. It's a ratio of less than perfect, in my understanding. Larger decimals are closer to 1, which is "perfect" but impossible in air.
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