What is the difference between the G1 and G7 measurement of ballistic coefficient measurements? I've seen both and the G7 number seems to be a lot lower? Reading up on ballistics and couldn't figure this out. Thanks

Here's little bit about it. Ballistic coefficient - Wikipedia, the free encyclopedia Also, do a search on this site for Brian Litz. He's the balistician for Berger Bullets.

In layman's terms, it means that the G1 is based on a flat based spitzer and the comparison between it and the new boat tail bullets will give you a much higher BC. The G7 model is closer to the new bullet shape and this will give you a lower BC . The G1 is preferred by some bullet makers because of the higher numbers . But for the long range shooter the G7 will be closer in calculated trajectory to your actual bullet drop so it is preferred for long rang shooting when calculating cold bore shots at long distances. J E CUSTOM

Found this well written and easy-to-understand reference: Berger Bulletin ยป A Better Ballistic Coefficient

+1 on JE Customs post. I have found that the G7 come ups were much closer to my actual findings using the high bc Berger bullets than the G1 values.