Wind Reading

Ok here is a topic that should generate some interest and also lots of debate. First of all wind reading is all about knowing your rifles true wind zero and grouping capacity on the target. (Some terms here need clarification further down).

Prior to the first shot fired what do you know about your rifle and what is its true zero. Did you sight it in on a absolutely still day in the morning where there is little wind, did you have your flags up when you did it. Some folks sight it in a 100yards then wind up the clicks to where the sight book will have you believe is 500m.

Lets start at the basics

A true Zero point of impact at 500m on a known range that you use alot.
Adjust your scope turrets so they are actually on Zero for elevation and for windage.

This is purely a datum reference point. NO TWO ranges have the same zero point. A difference in Altitude, terrain, temperature, Degree angle to targets always play a part in the true zero of the rifle.

What do you do at the range?

First of all, in your warmer target you need to use this target as the re zero of your rifle on a particular day and right down the elevation for this range and have this writting in your book before you fire your first shot the next time you come to this range.

You can fire a 60.5 on the warmer and well done but you have learnt nothing, and it means nothing except you have a great target in the gun room for braggin rights.

Once you know your zero and then fire your first shot in the splash plate what pre shot checks have you done. Are the flags the same as when you fired the warmer NO they are not. Wind, mirrage, temperature are a constant variant however wind does come in cycles and this is where you are starting to learn to read the wind.

It is not the strength you need to learn but the cycle of strength when to shoot and when not to.

Now lets move on to the grouping capacity of your rifle. If your rifle is not capable of holding a 7 ring group at 500m then no matter how good a condition reading your are the rifle just isn't up to it, so improve the accuracy of your rifle i am yet to see a rifle that will not shoot.

Every rifle has a natural harmonic and this harmonic is the true accuracy potential of your rifle. There are any number of personal exploits of shooters who claim super small groups all the time but are they in the top section of the field if not why not if the rifles group so well.

The reason is a "super grouper" barrel is always only going to produce great targets if the person reading the conditions gets it right with the averages of the conditions on the day.

If your rifle groups 3 ring hold and no smaller your margin for error is expodentially smaller than a rifle that groups in the 9 ring.

After much research and heart ache and nearly a tomatoe stake for a 300 Ackley i have finally got it working and at the Harry Madden produced a 54.2 target with 9 for group and this was the last target for the day. This rifle's accuracy potential now is less than 2" at 500m. Therefore if i have a wind change that drifts my projectile 2" then the wind group centre is 4" so at worst i will get an 8 ring shot if i don't correct but with a margin of correction then my group centre will remain 2" across the target. ( hope this makes sense)

Before any tells you they know exactly what the wind is doing 5klm or 8 or what ever how can they judge wind on your rifle when they don't know its accuracy potential or group centre.

more to come
Les

Les

The 500m fly shoot is a real challenge to score well in. I guess partly because many shooters that travel to the comps do not get to practice at 500m regularly. I may be wrong in that but I'm one that does more practise and club comps  at 300 than 500m, so what  do you think a shooter should be doing at closer ranges than 500m to determine a wind zero and rifle grouping potential that will lead to a 7 ring group average at 500m if their wind reading skills are ok.

Firstly on determining wind zero. What I do is sight it on a still day at 100m to avoid the effects of what little wind there is that can alter the bullets path at longer distances.

Let's say you get to a range other than your home range for a comp, do you then re- check your wind zero at this range just at 500m or at a closer distance?

Second, in regard to rifle grouping potential at what distances are you working on your groups and how many shots per group to determine if it will hold the 7 ring (4.25") at 500m? Its been mentioned before in this forum that 300m fly 5 shot groups of 1-1.5" are a suitable average to achieve 4.25" groups at 500m given average wind reading skills. At the Little River range where its often windy we test at 150yds looking for a 5 shot ragged hole group.

I think then that the different ranges we each practise at, whether they are public or private ones, determine how we work at setting the wind zero and getting the rifle to shoot small groups. I'm always interested to hear our other fly shooters go about practising and preparing for comps.

Nick

hi Nick i sight my rifles in at 500m because that is the range we shoot the reason for this is you have to ensure that your cross hairs or sight axis is perfect if you are going to sight in at 100 then just wind up.

There are two zero's for every rifle a zero at your range as a reference point and a true wind zero at the range you are shooting at. As an example i have zeroed my rifles for Canberra and if i travel to little river i an one click above in elevation to have a zero there.

The zero on your scope is just a reference point but a very important one if conditions get rough thought. Without it you could find yourself off the paper if the wind changed directions.

As for group shooting i do mine all at 300m and i work on getting less than half inch for 5 shots. Still day morning groups, lots of flags out, 5 shot groups,

cheers les