Went to the range today to do some load testing and had to deal with wind gusting fron 20 to 35 miles an hour. It was coming from my right rear and causing a whirlwind inside the high walls that border the range on the sides and target butts. I had a tough time keeping all my shots in groups of 1 1/4 inch at 100 yards with a 223 using 55 grain balistic tips. I had one flyer that opened up the group to nearly 2 inches. All considered I guess that much wind can easily move a light bullet an inch at 100 yards. I also had some 52 grain match kings that seemed to be less affected by the breeze but still a 3 shot group less than an inch was a good one today.

[ 04-21-2003, 00:48: Message edited by: rickt300 ]

Depending upon the angle that wind at a 90 degrees to the paper horizontally could mean as much as 1 to 1.25 inches at 100 yards. You did very well but didn.t get any meaningful data.

I think the wind blowing against me and the lightly held rifle could easily move a bullet a couple of inches off at a hundred yards. I did get the rifle sighted in exactly 1 inch high at a hundred yards but I really could not tell which bullet shot better than than the other. Guess I'll have to try it again on a less windy day.

Don't try to do any serious load testing when the wind is more than about 10 mph, but even less is better.

A dead-calm day is hard to come by where I shoot, but on those rare occasions absent wind, I've been astounded at some of the groups that a good gun will shoot. One still day, I found that my lil' old .222 would do three shots into 1.4 inches -- at 300 yards! Wind can make all of the difference in the world.

I sometimes make a practice of working up loads and chronographing the evening before, then getting up in order to be at the bench at very first light the next morning to do target work. Typically, even in otherwise windy country, you can get in thirty minutes to an hour of fairly wind-free shooting during the first part of the day.

According to Pointblank, a 10 mph wind deflection on a 55 btip will be about 0.8". 30 mph, 2.4".

At 200 yards, 3.48" at 10 mph, which would equate to just over 10" at 30 mph. HTH, Dutch.

Somewhere I read that a crosswind will in addition to left-right deflection, will cause up-down deflection also. And dependiing upon left or right wind, one way deflection will be up and one way down. Also dependent on left or right twist. Can't remember where I saw this. Maybe somebody here can quantify it for us.

Dave

It's called precession in a gyroscope I believe.
When force is applied to a spinning object the direction of movement of the object is 90 degrees to the direction of force applied insted of in the same direction.

One of the physicist on the boards here can probably explain it better.