Originally Posted by Jordan Smith
Originally Posted by Garandimal
Originally Posted by Jordan Smith
Originally Posted by Garandimal
Is this a difficult question to answer?

What is the wind difference, of known BC, at 400 yds.?

Or drop, for that matter?


BC's only real value is Energy down range.

... and the .270 Win., even w/ flat based PSP bullets like the 150 gr. NP, has plenty for most game, even at 400 yards.


BC - is a placebo for marksmanship.




GR
You're on the wrong track, here. First, energy down-range is about at the bottom of the list of reasons why high BC helps. Second, missing your target is all about errors and error stack. BC is not a placebo for marksmanship, unless of course you define marksmanship as using the lowest shooting technology possible, but rather high BC aids marksmanship because it reduces uncertainties, and consequently reduces errors (where error here is the difference between your guessed/intended value and the true value).

A couple of years ago I built a computational model that helps visualize the errors involved in external ballistics, similar to Litz' WEZ software. It simulates a number of shots taken in identical conditions, but where there is some uncertainty in the value of various parameters. This helps illustrate the benefit to higher BC.

In the following 1000-shot simulations the target width is 17.7", and I've assumed a shooter/rifle capable of keeping all shots within 1 MOA from POA, full-value wind speed (including gusts) of 12+/-7 mph, distance of 400+/-1 m, velocity ES of 20 fps, RH of 50%, temp of 46 F, and absolute pressure of 26 HgIn. The only difference between the two is the bullet and the MV. You can see that BC can make a big difference, even at 400 meters, even with the lower-BC bullet having a MV advantage.

.277 150 PT at 2950 fps:

[Linked Image from live.staticflickr.com]

.264 147 ELD at 2700 fps:

[Linked Image from live.staticflickr.com]

And this is my point.

Academics.

In a 20-knot gust environment?

I'm not shooting at game at 400 yards.

Why?

Because with all your academic high-technology... you don't control the wind.

How does your High BC wonder-bullet respond when you took the shot, and it was +/- 20 when you pulled the trigger?


A marksman and ethical hunter would know better.

... and get closer.


BC - is a placebo for marksmanship.




GR
You failed to see the point, even when it was displayed in front of your eyes.

The simulated wind was 12 +/- 7 mph, not +/- 20 knots. And even in that wind, with the gusts, in this particular example the 6.5 kept all shots within about 12", or approximately the vital zone of a BG animal, while the .270 did not.

+/- 20-knots?

No, you failed to grasp that your academic snow-globe of artificial constraints was ruined by a little real world probability.

Or, does your computer simulator control Mammie Nature as well?

Shooting at game animals.


BC - is a placebo for marksmanship.




GR