Ballistic Coefficient over 1.0

[choprzrul]

Ok, so I am looking at the Hornady 50 Cal .510 750 gr A-MAX bullet. It has a ballistic coefficient listed as 1.050. It has always been my understanding that a higher ballistic coefficient (i.e. .400 is better than .350) has less wind resistance and that ideal ballistic coefficient is 1.00. That 1.00 is a theoretical number that can only be achieved with zero wind resistance.

So where am I off here? If my understanding of ballistic coefficient is indeed correct, then 1.050 should actually gain speed going down range??? Yikes, what is going on???

[choprzrul]

Here is the link to that Hornady bullet: http://www.hornady.com/store/50-Cal-.510-750-gr-A-MAX/

[buffybuster]

Pretty certain that is the G1-BC that is listed for that bullet. That AMAX bullet is similar in configuration to a Very Low Drag (VLD) bullet. There are quite a number of different BC form factors (G1 thru G8). What that BC of 1.050 is telling you is this bullet exceeds the form factor G1 drag model. If Hornady used a G7 drag model, which more bullet companies are adopting for their VLD type bullets, the G7-BC would probably be around .5-.6 (which is still very high G7-BC).

Addendum: BC is not a static value. It changes with the velocity. Sierra shows G1-BC data but it provides the BC for various velocity ranges. This is because the bullet does not follow the G1 form factor and corrections must be made.

[Ugly Dwarf]

Perhaps others will contradict me, but the short answer is:

Yes, bullets can have a B.C. higher than 1.0, though it's uncommon.

Yes, bullets with a B.C. higher than 1.0 will fight drag better than bullets with a B.C. lower than 1.0.

I assume you're kidding, but No, a bullet with a B.C. higher than 1.0 will not accelerate as it travels down range. That said, they will decelerate slower than bullets with a lower B.C.

I can't speak for everything in the included links, but they seem to agree with what I have understood. Happy reading.

http://www.answers.com/topic/ballistic-coefficient

http://www.exteriorballistics.com/ebexplained/articles/the_ballistic_coefficient.pdf

Regarding the Magic B.C. of 1.0, I heard a story once about it being the B.C. of a .50 BMG bullet being measured when much of the published research was being done. This later became the benchmark for most other long range bullets. I don't know how accurate that story was, or if I mis-remember the story.

[264charlie]

Pretty certain that is the G1-BC that is listed for that bullet. That AMAX bullet is similar in configuration to a Very Low Drag (VLD) bullet. There are quite a number of different BC form factors (G1 thru G8). What that BC of 1.050 is telling you is this bullet exceeds the form factor G1 drag model. If Hornady used a G7 drag model, which more bullet companies are adopting for their VLD type bullets, the G7-BC would probably be around .5-.6 (which is still very high G7-BC).

Buffybuster is correct G1 BC is no good for this type of bullet. You to look at the G7 BC.