Thread: Question about BC

2nd picture:
Left - Hornady 140 eldm (G1 0.646)
Right - berger 130 vld (G1 0.562)

Now I know that you simply cannot look at the bullet and say what the bc is, but in saying that the high bc bullets without exception are longer (in it's class) and sometimes seem like their boat tial is longer. If their bc where close I wouldn't have asked the question but almost 0.1 difference is quite substantial for bullet looking so similar. The berger bullet even has a longer boat tail.

Opinions? Explanation for this? Hornady is pretty honest with their bc's so I don't believe inflating bc's are the answer.

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The heavier bullet has the higher BC.
BC = SD x form factor
There are limits to what you can do with form factor (bullet shape) as you run into stability loss if it's long and I'm not sure maybe bearing surface and ogive shape make it harder to tune.
Weight on the other hand can be increased quite a lot.

Like Bagheera said, weight is important. Take the 140 and hollow it out, remove the lead. The form factor would be the same but the BC would be utter shite.

Originally Posted by Bagheera

The heavier bullet has the higher BC.
BC = SD x form factor
There are limits to what you can do with form factor (bullet shape) as you run into stability loss if it's long and I'm not sure maybe bearing surface and ogive shape make it harder to tune.
Weight on the other hand can be increased quite a lot.

Light bulb moment. Been using the "throw a heavier rock (if the same form) vs lighter rock and heavier will carry more energy for longer and less wind sensitive" explanation for very long and somehow I didn't think of it myself haha.

Completely agree

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BeCause

Litz says G1 .564 on the Berger and G1 .587 on the Hornady with his testing method. ???

Lets say we have 2 projectiles, and both weight 150gr. One is a traditional lead core ELD type projectile (lets say like an ELDM) and the other has an aluminium inner in order to make it longer, but keep the same overall weight - the one with the aluminium core will be the same weight but have a significantly better BC as its longer for its given weight. The other way to significantly increase the BC without adding weight would be to make the projectile longer by having a large air cavity up the front, thus increasing length/BC while keeping weight the same. Its not so easy to put into practice though due to issues with making sure the projectiles are properly balanced when you start getting exotic with their construction.