G7 Ballistic coefficient question

[gunn317]

I am a little confused on this right now, I know that 6.5 creedmoor 140 gr amax per Litz G7 has a coefficient of .299. I was under the impression that berger vld is made to out perform and "buck" the wind. Shooter gives the berger vld a Litz G7 as .282 which means that it performs worse than the hornady amax?????? And on top of this the hornady 120 gr amax has a G7 of .465. If higher is better then why does the 120 gr amax have fewer minutes to get to 1000 yet is 1.75 minutes more and performs worse. Sorry for my confusion, I thought I was grasping this until I started looking at different coefficients

 

[djskit]

JBM Ballistics shows the Berger 140 VLD (litz) at .313 G7 and the 140 AMAX .299 G7.
It lists the 120 Amax at .465 G1, Litz/G7 was not listed. G1 and G7 can not be compared. Apples to oranges.


I'm sure you could find it the G7 somewhere, but JBM is where I go when sitting at my desk with the internet. It wil be less than the 140. You can look up the G1 for the 140's to compare.

EDIT - OK, I did, the G1 for the Berger 140 Match VLD is .640. 140 Amax is .585.

EDIT: The Berger 130 VLD is listed at .282 G7. Generally speaking, comparing BC's of different weight bullets is a dead end. The 130 can be driven faster than the 140, which may or may not make up for the lower BC. But you can play with those numbers yourself and see what happens.

 

[Rthur]

Don't get all fired up about the listed numbers. Find your load on a given bullet choice and shoot it. A chrono will be nice for a baseline dope. Take your load to range and see what it says/does.

R

 

[_Windrider_]

I bet if you wait long enough Mr. Litz will respond.

 

[gunn317]

I am definitely trying not to get wrapped around the numbers, just trying to understand and was looking at ammo available. I can get 120 amax match all day long yet all I have ever read was that 120s don't give you any of the benefits of the creedmoor in regards to reducing wind calls etc. I was also looking up numbers for my stepdad for .243 and .308 so I was surprised at the numbers and I know they are way beyond my level of comprehension right now. I guess the best advice is to get out and shoot and not worry about it and don't compare apples to raisins.

 

[Ring]

123 amax g7 = .2535

 

[djskit]

I am definitely trying not to get wrapped around the numbers, just trying to understand and was looking at ammo available. I can get 120 amax match all day long yet all I have ever read was that 120s don't give you any of the benefits of the creedmoor in regards to reducing wind calls etc. I was also looking up numbers for my stepdad for .243 and .308 so I was surprised at the numbers and I know they are way beyond my level of comprehension right now. I guess the best advice is to get out and shoot and not worry about it and don't compare apples to raisins.

Remember, lighter bullets generally have lower BCs, but can be driven faster, which will make up some of the difference with the higher BC heavier bullets. You can compare the BC's of bullets of the same weight and caliber - but once you change weights or caliber, you have to factor in the speed at which they are likley to be driven to see which one is the "best".

That being said, my 6.5 creedmore shoots 139 Scenars very tight. Are there higher BC bullets? Yes, but I've tried the VLD's and my rifle doesn't like them so the higher BC is irrelevent.