Wind drift question

Johnn Peterson

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I've played a 'little' with the Hornady calculator on this question. I
reload a Barnes 225gr TTSX BT for my Sons 338 WM. Ballistic coefficient of .433, velocity 2700f/sec. With a brisk 45 MPH breeze at 90 degrees to the bullet path, at 200 yds what would be the bullet drift? A little over 9", or am I way out of whack??? Help.
 
Well Johnn, my guess would be that under those conditions, 45 MPH cross wind, the drift at 200 yards would be more like three feet.
Bruce
 
Gotta agree here. That's gale force and I wouldn't want to even shoot in that, and definitely wouldn't want to hunt in it

Agreed and I wasn't advocating hunting and shooting under the set of circumstances I made mention of. Just trying to get some reliable info by those more knowledgeable in that aspect of shooting.

Bruce,
My initial very rough calculation seemed to indicate 91" but I was PM'd that I was one decimal point too much and actually, it seemed a little much to me as well. ;) That's why I thought I'd post the question and get some reliable info from someone on site with expertise that knows. All input and info appreciated guys :) .
 
That wind may move the shooter and rifle as well not just the bullet. My calculator says 14.4" 2303fps 2651 ft lbs. It's the mrx bt bullet that matches your 433 BC in my calculator
 
I have shot deer in big wind storms but shots wear well under 30 yards
tough hunting in big storms nothing is moving even if you're in the timber and alders in cottonwood trees are downright dangerous
I have bin caught in a windstorm packing carving slate out of the mountains and had to drop my pack and literally run for the beach blowdown crashing around me big branchs just exploding and wishing I was at home or hiding in camp
 
That wind may move the shooter and rifle as well not just the bullet. My calculator says 14.4" 2303fps 2651 ft lbs. It's the mrx bt bullet that matches your 433 BC in my calculator

From my #4 Barnes manual, that 225gr BT has a ballistic coefficient of.433. In the ballistic tables in the back of the #27 Hodgon manual, at a velocity of 2700f/sec, the flight time listed for a 200yrd shot for a bullet with that ballistic coefficient is 0.1157 sec's. This is basically the info I tried to apply. :confused::confused: . Was hoping perhaps someone into that variable in long range shooting will be able to clue me in.
 
In the Sierra Infinity, the nearest I could find was a 225 grain Hornady with a BC of .430.
Wind drift would be about 14.5" at 200 yards using an elevation of 785 feet.
 
That number sounds about right. Perhaps get yourself a constant so you can do the wind in your head.

^^^^^^^^^^range(100s)*wind ( in mph)
Constant=. ________________________
^^^^^^^^^ Wind data from computer

Then do mentally 2*45/constant = wind hold( convert to whatever inches or cm if you want, but no need)

Sorry about ^^^, Im having issues with my keyboard tab key.
 
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I ran the numbers for myself on JBM, and sure enough it comes up as 12.7". This is fairly close to the SWAG I use to calculate drift in the field: wind speed (mph) X range/100 which is then divided by 15 the constant used out to 500 yards, that reduces for each 100 yards beyond 500 out to 1000 and = drift (MOA). This gives me 6 MOA or 12". Something to consider is that the logarithm fails to take extraneous elements into account. One element that anyone who has watched a wind flag, or a wind sock, for any time knows, is that wind gusts are significantly stronger than the steady state wind, and that the direction of the wind is variable within an arc of some degrees. When the wind is blowing hard, there is only one viable shooting position, and that position is prone, or you can't hold on target. Well if you shoot from prone, unless on an elevated platform, or shooting from the crest of a hill, the path of your bullet moves in close proximity to the ground, and the wind along the ground tends to be slower than the wind a few feet above it. If you want a good head scratcher, watch snow blow along the ground in a different direction to the direction indicated by the flag. JBM doesn't take a bullet's rotational velocity into account, so the assumption is that drift is equal whether the wind is from 90 degrees or 180. Both terrain and wind direction can create a vertical dispersion in the expected trajectory, and practical marksmanship becomes a challenge when being buffeted in a strong wind. So drift in a 45 mph wind is whatever you observe it to be. Predicting drift when wind speeds exceed 20 mph is exceedingly difficult. I would be hesitant to shoot at a live target that wasn't at 0 or 180 degrees to such a wind, and even then, it would have to be from prone or I'd pass up the shot.
 
:) Thanks Boomer. A good in-depth explanation and assessment. Here on the island, considering the terrain and vegetation density, long range shots under very windy conditions aren't circumstances I have to contend with. On the flip side of the coin, a gift of an Antelope hunt a couple of years back in southern AB, did give me a 'glimpse' at some longer than on Vancouver Island range conditions.
This wind factor question was something my Son asked me about so I informed him I'd inquire and get back to him. Thanks again for your input. Much appreciated :) .
 
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