Bullet Drift - how far?

[TFinalshot]

Is there anyway to logically estimate bullet drift over known distance's and wind speeds? I wonder what a 30 MPH cross wind would do to a 150 gr. bullet shot from a 300 WSM at 250, 300, 350, and 400 yards?

I deliberately did not shoot a very nice mule deer buck this weekend because I did not want to wound him. I estimated him to be about 300+ and directly accross canyon. The distance was not a problem, but the 30 mph cross wind, with gusts to 45 was!

As it turned out, I sat on him for more than 3 hours thinking he would get up and move down off the cliff. Well, he got up fed around for about 10-15 minutes and some joker started blazing away at what I thought was at least 400 yard shot, could have been more, (with a 30mph cross wind) and wounded him. I'm not sure they ever found the buck. Last I saw the buck was moving up hill and into the next basin like he'd not been hit. Only problem is I know he was hit cause he went down like a tone of bricks, stayed down for about 2 minutes and then sprang to life and ran off like nothing had happened, go figure!

Finalshot

 

[RLH]

most good reloading manuals will have some info on bullet drift. it's a real hard thing to guesstimate. i usually aim off to the side the wind is comming from and look for the dust and try and compensate for the 2nd shot. also use the same process as a range finder. i watched a show on tv the other day called "best of the west". the guys on that show have some real experience with wind and long range shooting in the field. about as impressive as anything i've ever seen. don't know if i've ever seen better shooting, anywhere. much less in the field. shot a coyote at over 1000 yds. i'm sure the tape they are selling on that show would have some good wind info. personally, i'm a tracker and don't shoot too many real long shots. sometimes out to 400 yards or so, but usually inside of 200. while the wind can drift a bullet substantially in 200 yds, aiming a foot or so to the windy side will usually put it in the animal. that's if it is a real hard wind. where the wind really screws me, and i'm sure it's the same with most folks if they think about it, is that it makes it real hard to get off a good shot. gusts hit you and move you causing a bad shot. and then if you're compensating for the wind, it will quit for a second, right when you shoot. the wind effects me personally, more than it does the bullet. a friend shot at a muley buck in horrible wind and very steep uphill. there were 4 big bucks in a line. he shot at the front one and hit the 2nd one. that was ok, because i shot the front one the next day and it was bigger. another thing that makes it almost impossible to make a good guess, is what is the wind doing between you and the deer? if it's a fairly long shot, 300 yards or more, there can be all kinds of stuff happening between you and the deer. wind may be less or more. i'd say next time it's real windy, go out and do some shooting and see what you and your rifle can do. bank that in the brain and use it next time. i know one thing, i've never been in wind hard enough to keep from shootin' at a good one.

 

[rost495]

FS

BTW I should have put this in the other reply.

If you get good charts made for your rifle you can buy a digital non directional wind speed meter that is extremely accurate. For shots of say 300-400 yards you can become quite deadly using it. You have to gauge the direction of the wind carefully on a clock scale and use a good drift chart for your rifle though.

Anything longer than that and you start to encounter (possibly) badly layered winds. And if in the mountains as we know you are, anything further has high odds of drafts coming up draws etc...... So the effect can be multiple on drift. The initial cross wind starts the bullet on an angle that cannot ever recover unless you hit an opposite cross wind. But due to differing layers and angles of winds on longer shots, the bullet can start drifting, hold its own, hit another layer and drift more, hit a slower layer and not drift as far etc.... When compared to a flat 15mph wind along the whole course of flight.

For 1000 yard shooting it gets to be really confusing.

Its why I won't shoot long shots unless its calm. Last years 802 yard shot on my caribou was simple because it was almost totally dead and there was a tiny mirage to show that it was just a shade of breeze to affect the flight. Had it been a norther or worse, it would have been a really unethical shot.

All this being said, you are the one who calls the ethics side. If you are going to attempt the shot you owe it to the game to be as advanced as you can. Its why I carry a wind meter and drop and drift charts along with my rangefinder. And I've fired my gun at the actual distances to verify or modify the charts and I try like crazy to fire at 600 in various wind speeds to verify the drift charts. If not at 600 I do it at 300 for sure.

Best of luck, Jeff