Bullet BC's

[shedhunt]

I have been reading about bullet bc's and have noticed in several articles that I have read that people have also quoted G7BC or G1BC, what do these mean compared to BC's that I have looked at on boxes of bullets or on web sites from ammunition manufactures?

 

[wnc-coyote]

Generally the bc's listed are g1. Most if the time if it is a g7 bc it will say so. I am no expert so if I am wrong about this someone correct me. From my understanding g1 is based off flat based bullets which when using high bc bullets such vld's will not always compute right. G7 is based off of new boat tail designs. The reason most manufacturers still post g1 bc's is for the apaerance of a much higher bc. For example a .277 150gr hunting vld list a .531 g1 bc or a .272 g7 bc. You can also go to betters website they have a page on the diff.

 

[Joe King]

Generally the bc's listed are g1. Most if the time if it is a g7 bc it will say so. I am no expert so if I am wrong about this someone correct me. From my understanding g1 is based off flat based bullets which when using high bc bullets such vld's will not always compute right. G7 is based off of new boat tail designs. The reason most manufacturers still post g1 bc's is for the apaerance of a much higher bc. For example a .277 150gr hunting vld list a .531 g1 bc or a .272 g7 bc. You can also go to betters website they have a page on the diff.

You got it right. G1 being a modeled on a flatbased spitzer, and G7 being modeled on a boat tail spitzer. Each base (meaning basic bullet design not referring to the base of the bullet) design behaves differently in regards to exterior ballistics.

 

[Mikecr]

Berger Bulletin » A Better Ballistic Coefficient
https://en.wikipedia.org/wiki/External_ballistics

 

[shedhunt]

Thanks everyone for the great information. I will look into this more with the knowledge that has been passed on and see what the actual BC's are on the bullets that I have been shooting up to this point and if I will be looking to keep them around or change.

 

[Bart B]

Shedhunt, note also that while Sierra Bullets' uses several BC's for a given bullet at different velocities through air based on their G1 standard, Berger uses only one based on their G7 standard. This may cause some confusion when comparing bullets from each maker to each other.