Wind drift?

[Oregononeshot]

I was out shooting my 54 at 100 yards today, getting it fine tuned for my elk hunt this fall. The wind was blowing from left to right 0-5 constant with gusts up to 10 (my best guess). My impacts were a consistent 6 inches right. I tried to shoot only when the wind was not blowing (not sure what it was doing at the target). 6 inches seemed like a large amount for such a small wind, what have you guys experienced? I'm shooting 535 round balls.

 

[biliff]

A rough rule of thumb is at 100 yds, expect 1 inch of drift for every 1 mph of crosswind component. There are RB ballistics calculators out there if you care to google them.

 

[SDSmlf]

Old school wind reading. Watch the leaves on the trees (if there are trees with leaves on them) down range. Try and time your shots when the leaves look similar to when you took your previous shot. If done correctly, will tighten up the vertical stringing from a cross wind.

And as a point of reference, a .530 diameter ball leaving the house at 1500 FPS will drift 11.5 “ at 100 yards per the calculator I use.

 

[biliff]

Old school wind reading. Watch the leaves on the trees (if there are trees with leaves on them) down range. Try and time your shots when the leaves look similar to when you took your previous shot. If done correctly, will tighten up the vertical stringing from a cross wind.

And as a point of reference, a .530 diameter ball leaving the house at 1500 FPS will drift 11.5 “ at 100 yards per the calculator I use.

Might want to include the wind speed used in the calculation

 

[SDSmlf]

Ok, had a couple of adult beverages before posting earlier and didn’t check my post, it happens..... or maybe just not paying enough attention. As you originally referenced, 5 and 10 mph, the drift at 100 yards with a .53 diameter ball starting at 1500 FPS, expect 5.7” and 11.5” horizontal drift respectively, per my ballistics calculator. If I am far off, anticipate a timely correction....

 

[fleener]

One of the things to consider is also that a 3 or 9 o'clock wind will have more impact on the ball then a 1 o'clock wind. Also the wind closer to the shooter will have a greater impact on the ball then the wind farther down range.

Fleener

 

[Rifleman1776]

One of the things to consider is also that a 3 or 9 o'clock wind will have more impact on the ball then a 1 o'clock wind. Also the wind closer to the shooter will have a greater impact on the ball then the wind farther down range.

Fleener

That's why judging hold with wind is called 'kentucky windage'. Ain't scientific, just experience and watching other clues like leaves and grass downrange.

 

[Big Rviers]

Rifleman1776 is right on the money. "Kentucky windage" and experience". I've seen hunters when guiding who could quote windage and elevation numbers to the decimal and didn't know RTT (range to target) worth squat. I taught Kentucky windage to new shooters with 22. cal rifles by placing colored balloons at random distances while the shooter looked the other way, then would say "red" or whatever balloon and give them 10 seconds to turn and shoot. Eventually getting it down to 3 seconds. Good practice and lots of fun. Our black powder shoots back home were the same, no posted ranges and field conditions only. Forget ballistic charts in the field its about elevation, windage, experience and knowing your gun.

 

[rafterob]

I had great fun about 3 years ago. A rather strong, steady cross wind so I decided to practice windage shooting.On a 30" wide target backer I was aiming a barrel width off the right side of the backer and hitting near center at 100 yards. My guess is about 6" off the target was the aiming point. I would estimate the wind was a good 15mph maybe more.

 

[fleener]

knowing the science behind bullet drop and drift is beneficial when in the field. It could/should help getting the experience part down faster if you understand the science behind it. I think experience and knowledge of what is happening go hand in hand.

Fleener

 

[Oregononeshot]

Unfortunately where I shoot there are no trees. Next time I'm going to bring a broom stick and attach flagging tape to it to see the wind at the target. Thanks for your info it sounds like the drift I was experiencing is about right given the wind

 

[Zonie]

I was out shooting my 54 at 100 yards today, getting it fine tuned for my elk hunt this fall. The wind was blowing from left to right 0-5 constant with gusts up to 10 (my best guess). My impacts were a consistent 6 inches right. I tried to shoot only when the wind was not blowing (not sure what it was doing at the target). 6 inches seemed like a large amount for such a small wind, what have you guys experienced? I'm shooting 535 round balls.

The roundball trajectory calculator on my computer says if you were using a powder load that would give a muzzle velocity of 1650 fps, a 5 mph crosswind will deflect the ball 5.8 inches at 100 yards.
A 10 mph cross wind will deflect the ball 11.7 inches at 100 yards.

Bear in mind, a person walking at a brisk pace is going about 4 mph and the last time I did that, the wind was barely noticeable.

That 1650 fps velocity is about what Lyman's BLACK POWDER HANDBOOK says a powder load of 90 grains of 3Fg powder would develop.

 

[Rifleman1776]

science behind bullet drop and drift

Just think: "this is like throwing a brick". All the science you need to know. If it were easy we wouldn't be shooting these things.

 

[Pete G]

...and don't forget that the wind can be totally different at the firing line and the target