New guy question re: wind

G

ghylton981p

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How much effect does wind really have on group size at 100 yards? Pretty fair wind no measuring tools. Local weather says 22 mph.
 
My 6PPC

ghylton981p said:
How much effect does wind really have on group size at 100 yards? Pretty fair wind no measuring tools. Local weather says 22 mph.
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Last weekend I shot my 6PPC using a 64gn bullet which leaves the muzzle at approximately 3240fps. A hand held wind speed indicator gave me a reading of 18 to 20 mph on at the front flag . The wind was left to right. The bullet displacement was around 1.35 inches at 100 yards. This seems consistent with what I was expecting.
Andy.
 
With no flags...

I would expect several shots together and some about an inch out....maybe more, maybe less...depending on how big and how fast the bullet.
 
more info

Sorry I didnt give enough info. Or at least what I have. .308 155gr Berger vld and I dont know the velocity I will soon as I do have a chronograph.
 
Crosswind

A 10 MPH, 90 degree crosswind will push a 66 gr. Boattail bullet with a B.C. of .28, with a muzzle velocity of 3,400 FPS, approximately 0.914 inches at 100 yards. Therefore a 22 MPH, 90 degree crosswind should move the bullet about 2.010 inches at 100 yards.

So, if you shoot all five shots into EXACTLY the same 22 MPH crosswind condition, the wind should have no impact on your group size, but, your group will build 2 inches over from where it normally does. :eek:
 
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Thanks

Thank you guys for your input. I assumed I could shoot the .308 today without much trouble. I was WRONG! My groups were off and crazy. Lesson learned....
 
A 6mm 105 gr. with a BC. of .557 @ 3000fps. and full value 10mph wind will move the bullet 1/2" @100 yds and 6'@ 1000yds……… jim
 
I test on what appears to be a well protected 100 yard range.

The wind does crazy things on this range. Every 25 yards it can be going in a different direction.

Without flags it is useless.

Another range I shoot at has a steady left to right at about 1 minute at 100 yards. When the wind shifts, you better have a good spotter.

22 mph is a waste of ammo.
 
ghylton981p said:
How much effect does wind really have on group size at 100 yards? Pretty fair wind no measuring tools. Local weather says 22 mph.
Click to expand...

Google up a free ballistics program and plug in your numbers. It'll show you the wind values at different ranges, at different wind speeds, bullet
velocities and different ballistic coefficients.
The real test is to shoot with good flags and an accurate rifle in a complete switch. In this part of the country we don't usually see big wind, but the switches are constant, very often. That's where a really good set of flags excel.

As was mentioned, there are several places near you that shoot the UBR format of benchrest shooting. It's a lot of fun and a great bunch of guys. Where are you in Ky? We'll have to get together and shoot. Bluegrass Sportsman League in Wilmore is just a short piece from Lexington. They hold Registered IBS and UBR score matches and I think they still are doing some unregistered group matches. UBR has a factory class. Come out and shoot. I agree about buying a good used rig, but load up a bunch of ammo and actually shoot at a match. You'll learn much more that way than just watching. BR is simply not a spectator sport, and even if you're not competitive at first, you'll still see what it's all about if you bring a decent shooting factory rifle and shoot it.

There are also ranges in Auburn, Ky. and Gallatin, Tn. Auburn is about 20 minutes west of Bowling Green.
As you can see, there are places to shoot nearby. Many on here have to travel a few hundred miles to shoot registered matches. You are in a very good location that allows you to shoot without ridiculous travel.

I'm in Auburn. Shoot me a message. I'll be glad to help.
 
Get aquainted with the JBM Ballistics program. You can learn a lot from playing around with it. http://www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi

You can also learn a lot by getting four "snow poles" or cheapo fiberglass fence poles from Tractor Supply and taping a couple of feet of surveyor's tape to the top. http://www.amazon.com/Driveway-Pole...UTF8&qid=1393003585&sr=8-1&keywords=snow+pole .

At first, don't try to be Mr Super Windreader. Just shoot all the group when the flags are all pointed in one direction. It might help you to limit yourself to three shot groups for a while.

If you can rig your cell phone to focus on the flags while you shoot your group, you will see some interesting things. Like "Dagnabbit, how did I miss that switch!".

PS: Don't put much, if any, stock in that local weather wind predication. You need to know what it is between your muzzle and the target. Much else isn't too helpful.
 
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mwezell said:
Google up a free ballistics program and plug in your numbers. .... to shoot registered matches. You are in a very good location that allows you to shoot without ridiculous travel.
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I suggest don't google. Google searches go directly to the NSA in Utah. Other search engines at, Yahoo, Ask, etc, at least go to your ISP before the NSA grabs it. The NSA already knows you have guns, using google just flags you as an active shooter instead of being someone who simply bought a gun, took it home, and put it in a drawer!!!!!
 
I wonder why this matters

JerrySharrett said:
I suggest don't google. Google searches go directly to the NSA in Utah. Other search engines at, Yahoo, Ask, etc, at least go to your ISP before the NSA grabs it. The NSA already knows you have guns, using google just flags you as an active shooter instead of being someone who simply bought a gun, took it home, and put it in a drawer!!!!!
Click to expand...

I am a little perplexed as to why it matters whether the NSA knows you use your firearms. I am not concerned if my Govt knows I shoot regularly in BR competitions or not. But I do live in Oz not the USA.
Andy.
 
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