DEALING WITH THE WIND PART 5
Understanding Groups Dealing with
the wind. Part 5 by Chris White
Fig. 3 With a 2½ minute group even though the first shot hits the V bull the next could just as likely be a three.
Now we have looked at why rifles shoot groups and do not put all the shots through one hole. We have touched on the importance of finding the centre of the group and ensuring that this group centre coincides with the centre of the target. This maximises our potential score; even if the combination of rifle, shooter and ammunition is not capable of shooting tight enough to put every shot into the bullseye.
We need to grasp the fact that getting the ‘vertical centre’ of the group on the horizontal centreline of the
For the smallbore shooter shooting indoors, group- centring is fairly straightforward but for the TR shooter, wind is usually a bedevilling influence. How we cope with the wind comes soon. Since we cannot predict what the wind will be until very close to shot delivery, we - unlike our indoor colleagues - are unable to centre the group in a lateral sense, in anything other than benign wind conditions.
What we can do however, is to centre the group in a vertical sense. The tighter the group the easier this is to achieve.
Fig.2 If the group size is one minute then the next shot could fall anywhere within the five blue circles.
V bull not only minimises the risk of losing a shot out the top or the bottom of the bull, it also gives us maximum lee-way with our wind judgement. If the shot falls right on the ‘waterline’ then we have (on an NRA TR bull) almost +/- a minute of error potential which, if we are shooting ¾ minute groups is almost entirely taken up by the size of that group!
However, since we are shooting at a round bull and not a square one, if the shot falls at 12 o’clock or 6 o’clock we have very little lee-way and even if our wind judgement is spot on our group size may lose us a point.
Fig.4 With a one minute group, the shooter is able to make rational decisions based on the plot and his wind- reading experience.
Fig.5 The shooter is flummoxed due to the excessive grope size. Shot placement frequently differing from his wind-reading experience.
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