Gary Chillingworth continues his investigation of long-range accuracy PART 3
Gary Chillingworth continues his mini- series on long- range accuracy – this month, wind drift
Last month, we looked at the viability of hunting beyond 40 yards with a sub-12ft.lbs. air rifle, and if you could get a tight enough group to make a humane kill. We looked at calibre and whether or not a .177 or a .22 was more efficient at long range. Our initial testing seemed to show that a .22 was affected more by the wind then a .177 and I couldn’t completely understand why.
So, this month I thought we would look at wind drift and how it affects pellets in both .177 and .22. I must admit that before I started the article, I was of the opinion that a .22 would take more wind because of the mass and size of the pellet. Before I became a train driver, I used to drive trucks and as we all know, an HGV weighs considerably more than a car, but due to the larger surface area of a lorry, they are affected more by wind and can easily be blown from one lane to another.
My other theory was that wind at the barrel was more important than wind further downrange. My belief was that if you could move a pellet off line by a degree or two as it exited the barrel, by the time it arrived 40 yards downrange, it would be a centimetre or two off line. Well, before I go any further and just in case you stop reading at this point – and I wouldn’t blame you if you did – I WAS WRONG!
NEAR OR FAR?
My plan was to set up a desk fan at the end of the barrel, I used my anemometer to measure the wind speed ( 6mph) and then fired a series of shots. With the fan switched off, all my shots landed on target – shooting a vertical line – and with the fan running, all my shots landed bang on target and touched the line; it had no effect. I then tried a hairdryer, which got the wind speed up to 13mph, and even though a few of the shots landed slightly to the left of the line, it was only by about a pellet width. Even though a 5mph wind would certainly move a pellet, the short amount of time that the pellet was passing by the fan and hairdryer was not enough to affect the flight path.
I am planning to hit the charity shops to buy about 20 hairdryers to repeat the experiment, but that will have to wait. The good news is, Maldon and District AGC is close to me, and I have managed to work on a few things and come to a conclusion. Luckily, at M. A.D. we have some nice open land and some convenient fencing, so I was able to hide behind this barrier and protect part of the flight path of the pellet.
By shooting in both directions, with a constant wind from left to right, I found that the wind downrange is far more devastating to a pellet’s flight path than wind at the barrel. When lying in open ground, with a 10mph side wind, and shooting into a sheltered area, the pellet hardly moved, but shooting from a sheltered position into an open field, the pellet always hit about 1.5cm left to right. To me, this made no sense,.
FOLLOW THE NOMADS
On Sunday, I shot at Nomads HFT club at the Spring Recoiling championship, and Nomads is the home of Airgun World’s Jim Tyler. Jim is quite simply one of the cleverest chaps I know, and when I get confused I always speak to him. I asked him why the flight path was affected more downrange, and why a .22 appeared to be worse than a .177, and this is what he told me:
‘It’s all down to flight time. When the pellet leaves the barrel, it’s travelling at just under 12 ft.lbs., but the further it gets downrange, the slower it becomes. As the pellet is travelling slower, this allows the wind to have more time to affect its flight path. This is also why a .22 struggles in the wind more than a .177 – it travels at a much slower pace than a .177, and this added flight time gives the wind more time to blow it off course’.
This leaves me with the problem of how we can judge wind downrange, when we are out stalking. Well, this is where some planning comes in, and if you are new to hunting or target shooting, judging the wind will be more important than judging range.
When you are in the field, you can obviously use a anemometer. If there is little cover between you and where you want your pellets to land, there is a good chance that any reading you take at your rifle will be similar downrange. The problem is, if you are in a sheltered position and shooting into an open field, taking a reading where you are, it’s of no use, and walking over to a rabbit warren to take a reading will work, but you won’t see any bunnies for the next few hours.
So, this is where preparation and fieldcraft comes in. Learn your plants
I now understand a little more about the way Mother Nature affects my pellets on those windy days”
and how they are affected by the wind. When you go out, take a paper target with a vertical line drawn on it and place it in an exposed area. Take a measurement of the wind and write it down, then shoot the target and see how far off the line the pellets move. Then watch the grass, cow parsley, leaves on trees and note down how much they move, do this for all different wind speeds and build up a data base – after a time, it will become second nature.
Another option, if you shoot in a regular place, is to leave windicators around – small bits of ribbon tied to trees, or maybe a small stick pushed into the ground with a ribbon attached. After a while, the rabbits or other quarry won’t even notice it, and you will have a perfect instrument to use. Just remember, if you are shooting along the ground, don’t use the tops of the trees to judge your wind. The higher you go, the windier it gets, so always judge your wind by where you are shooting.
I admit this has been a learning curve for me, and I am pleased to say that I now understand a little more about the way Mother Nature affects my pellets on those windy days, but no matter how hard I look into things, including the kit I can use, I cannot see any way that anyone should be using a sub-12 ft.lbs. air rifle in any calibre, to shoot any living thing at more than 35 yards unless the conditions are absolutely perfect – and even then, I wouldn’t go out beyond 40.
I will finish this piece with an extract from an email, received from a reader who wishes to remain anonymous.
‘Gary, if you are going to take rabbits at long range, then use an FAC gun, whether this be a .25 calibre, 40 ft.lbs. air rifle, 17HMR or 22LR, and if you don’t have access to a rifle like this, then work on your fieldcraft. The countryside gives us free food and great sport, and we owe it to the animals we take, and future generations of hunters, to treat our quarry with compassion and respect’.
I say, ‘hear hear’ and wish you all happy shooting.
Sheltering next to a fence showed me that the initial flight of the pellet is not that important
RIGHT: Target shooters use the bend in the string to gauge wind direction and speed
FAR RIGHT: As you can see, in the same conditions, the .22 takes nearly double the wind of a .177
RIGHT: Place a target next to grass and weeds and watch the correlation between pellet impact and movement of the foliage
ABOVE: Anybody can attach wool to their rifle to give an indication for wind direction
RIGHT: Jim Tyler is a walking encyclopedia for all things airgun