Effects of wind

[Colorado Redneck]

Today was the first prairie dog safari of the year. Have a new gun and was excited to try that out. Remmy 700 in .204 Ruger. Berger's 35 gr. bullet works amazingly well. A good hit just turns them critters inside out. Shot very similar to the 22-250 with 40 gr. blitzkings. Lots less muzzle blast. Going to learn to love that gun!

About noon the breeze came up a bit. The dogs were spooked so the only shots were long. When I finally got dialed in, holding about 1.5 inches up wind would nail them things. On Google Earth the distance looks to be close to 300 yds. That was my guess in the field, as I had to hold a bit over to hit'em. Both guns are zeroed at 250. The wind was nearly 90 degrees from the right, and I judged it to be averaging a bit over 5 mph. Just a wild a$$ guess.

The thing is, the trajectory calculator online shows the windage should be 4-5 inches for that velocity of wind and all the other variables. This has always been my experience. Even in strong breezes, where the wind gets down right annoying, the wind effect is lots less than the calculator shows.

Anybody have any comments?

 

[Brian Pfleuger]

I agree. Bullets always perform better than ballistics calculator project, in both wind drift and trajectory. I have yet to see an exception. I always switch the drag function to G2, which seems to be closer to reality.

 

[Colorado Redneck]

Which calculator do you utilize?

JBM is the one I been using.

OK. So after fiddleing around, the bullet selections is "None." Then you enter the info about the bullet, select "G2" and then the windage comes out about what I doped out in the field.

Thanks, man. That makes things more credible.

 

[B.L.E.]

Were you actually measuring the wind speed or is the wind speed your best guess?
Most people totally overestimate how hard the wind is blowing. When I did a lot of windsurfing, I had a little pocket aneometer and when it indicated 12 gusting to 18, people swore it was blowing 20 to 25.
Also, the wind is almost never the same speed all the way from the muzzle to the target.

 

[Brian Pfleuger]

Yeah, I use JBM too but I've also used several others and they're all pessimistic.

I always thought I was just over estimating the wind until I started shooting 200+ yards. Out that far, it became obvious that real bullets fly better than computer bullets.

There are probably exceptions, but 2 bullets in .204, 3 in .22-250 and 2 in 7-08 all match the G2 drag function almost exactly which makes me believe it's probably more common than not.

 

[Clifford L. Hughes]

Clifford L. Hughes

Colorado Redneck:

I will share with you what I learned reguarding doping the wind when I was shooting for several Marine Corps rifle teams. I didn't try to guess the winds speed because it most likely wouldn't be accurate. I plotted in my data book the range conditions for the day and I noted their effect on my bullet. Such things as blowing dust, blowing tree limbs and blowing grass: anything that would have an effect on the strike of the bullet. However, the primary method for correcting for the wind is the mirage as seen through a twenty power Bush @ Lomb spotting scope. As the heat waves drift up they drift angularly with the wind currents: the flatter that they are the stronger the wind.

Semper Fi.

Gunnery Sergeant
Clifford L. Hughes
USMC Retired

 

[tim s]

The other thing you may want to consider if you shoot in generally PIA western winds is switching bullets. The Bergers are fine bullets, very accurate, etc. The ballistic coefficient however is around 175-180. The BC's on the 40 vmax's and 39 Noslers are 285-300. That's a major deal out yonder. I have 2 20TAC's which are about the same ballistics and one gets 32's the other 40's and those 40's are good to go to about 500 yards [calm] 300 in most anything else.