DEALING WITH THE WIND PART TWO
B
efore we can deal with wind effectively, we have to have a ‘good zero’. Whilst this ought to be fundamental it is often neglected and ‘near enough’ is simply just not good enough!
Most rifle shooters have some understanding of the concept of zeroing so, we could expect that this would be straightforward. In terms of establishing an elevation zero it is straightforward. The wind zero is more complicated. We are into territory abounding with old wives’ tales, misconceptions and downright hokum. Indeed the term ‘zero’ in respect of elevation is itself redundant!
which coincides with the centre of the bull. When he is finished he loosens the screw on the scale plate and moves it until the zero line aligns with 200 yards on the range-scale. Now he knows that when he ventures to 1000 yards, he will only have to line his zero point up with 1000 yards on the range-scale and he will hit the bull - providing he has judged the wind correctly - or will he?
Dead simple one may say. Let’s stick with Jack for the minute. He goes to a few local shoots, setting his rearsight at the requisite point for the distance he is shooting and finds that, depending on the batch of ammunition with which he is issued, his sighters generally are in the black and he can quickly get into the bull. He gives little though to the fact that he rarely gets a bull with his first sighter.
Blair Atholl 2010 Scottish Open. All of these shooters will know their 900 yard zero!
Although we are travelling down the wind-reading route we may as well be thorough, so let’s start with elevation. Besides it is the easiest route into the issue.
Most experienced TR shooters will have a clear understanding of what they mean by their ‘zero’ in respect of elevation and that is that they will know what elevation to set on their rifle for a given type of ammunition at any particular distance. It is how they get to that point which we need to consider here.
Let’s look at this in a bit of a historical context with a fictitious anecdote. It is March 1958 and Jack has just bought a pristine No.4 rifle complete with a brand new A.J. Parker rearsight. He turns up at his local range for a pre-season practice session at 200 yards and buys a batch of DAC’43 ammunition which he knows is about as good as .303 comes. He lines the zero mark on the rearsight up with 200 yards on the range-scale and fires a shot - which strikes the bottom of the target.
He adjusts his sights accordingly and, by trial and error, ends up with a group of shots the centre of
Come May he is brimming with confidence and takes himself off to Bisley to shoot in a big open meeting where he is issued with FN ammunition. His sight settings are near enough at 200 and 300 yards but setting them at 500 yards produces a shot two MOA high and at 600 yards, almost three minutes high. When he repairs to 900 yards, his first sighter results in the target being pulled down and returned clear with a miss being signalled.
Now the moral of this story is that the range scale has been graduated for ammunition with specific ballistics in an ideal rifle. Not all ammunition behaves the same and not all rifles behave the same. If Jack had paid attention to the other side of his elevation scale he would have seen that when he’d set his scale at 200 yards that clever Miss Parker had arranged things so his sight was reading five minutes. There is a point to this which we will come back to but, just before we leave range-scales, we need to understand that if we rely on them we are likely to be in a bigger mess than Jack was!
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