Wind relation to group size?

[shrewster56]

Well i think this flier problem is starting to improve now? Can anyone tell me how much differance it would make shooting from the bench with a quartering toward me head wind of 18kmh with gusts to 25kmh as oppossed to if it were dead calm or no wind at all.Yesterday am i shot a nice round three shot group or perfect triangle at 100yds in the wind i described and was 1+1/4" center to center.I had no flags to judje the wind.The scope must be fixed now?My question is could i expect about a 50% improvement in the group if there was no wind at all.I also fired a shot at 200 yds 10x power and hit 1"high and 3/8ths"right of center,my group at 100yds was 2"high to the center of the group.This post relates to the flier post below and it was moved to the reloading forum.Thanks for all the help everyone..Shrewster56

 

[Phil]

If your gun is shooting 1 1/4 inch groups at 100 yds, I would not expect any miracles in calm conditions. Without wind flags to tell when you have a stable condition, it hard to say what to expect.

 

[Tree Doc]

Not accounting for the gusts, the crosswind component for an 18 kmh wind would be 12.7 kmh. Now what you need to know is bullet weight and velocity. these parameters can be plugged into an equation that would give you the precise amount of windage effect that bullet is experiencing. Not knowing the bullet info, it's hard to say how much windage you'de have to adjust for but from experience, at 100 yards I would think you would be in the area of 1/2" windage adjustment.

The flyer could be caused by gusts but depending on how far out it is I find it more a component of gun barrel or ammo.

 

[shrewster56]

Thanks Phil and Tree Doc for the info.The bullet is a hornady 154 gr sp and the vel is 3000 fps 15 ft from the muzzel.The wind was comeing toward me diagonaly at about 45 Degree angle.So if i could tighten up the group by 1/2" at 100yds this would make it about 3/4" in calm conditions.This is closer to what the rifle would shoot befour i had problems..Thanks a bunch for your input..Shrewster56

 

[Val]

Try this Ballistic Calculator:
http://www.biggameinfo.com/BalCalc.aspx

It will give you the affect of a cross wind. Some vector analysis needs to be done to determine the crosswind component of a wind at an angle. A 45 degree wind at 18 MPH would have a cross wind component of 9 MPH.