Target Sports

TARGET RIFLE BASICS: READING THE VERNIER

Created on 27th May 2009

CHRIS WHITE gives a simple guide to the Vernier scale

AFTER THE last session, you should be able to set your sights to five minutes or any multiple of five, 10, 15 or 30, for example. How do we set the sight to a number that is between a five-minute increment, six for instance? Firstly, we know that six is between five and 10. Therefore the zero line on the sight will appear somewhere between five and 10. Hopefully that is pretty straightforward. The next bit is the part some people find complicated. Six is five plus one. To set six minutes on the rifle, the zero line is above five and the first line on the vernier must align with a line on the elevation scale.

In this case it is against 10. Look at figure 1. Now this is the clever part of a vernier. When the elevation is set at six, only one line on the vernier scale appears aligned with a line on the elevation scale and this is the first one. This will pertain at any elevation setting that is one minute above a five-minute increment: 11, 16, 21 or 36 for example. That's easy isn't it? Now you are well on the way to being able to read the vernier. Remember what we covered last month about how the vernier is constructed: "One scale is the rifle's elevation scale and it has graduations on it in increments of five minutes and multiples thereof and (probably) numbers at 20 minute intervals. The other scale is the vernier and has six graduations on it."

This is very important. Two of the divisions on the vernier are zero and five. As we saw last month, when these two divisions line up with the elevation scale we will have either five minutes or a multiple of five minutes set on the elevation and this is the only circumstance under which two lines on the vernier will align with the elevation scale at the same time. Between these two divisions are four other divisions. By lining the appropriate one up with the elevation scale we can produce an elevation setting which ends in one, two, three and four or a setting that ends in six, seven, eight and nine.

Now take your rifle and set 13 minutes on the rearsight. Remember the zero line on the vernier will be between 10 and 15 minutes on the elevation scale and the third line on the vernier will align with a line on the elevation scale: in this case 25. What you have should look like figure 2.

Practise setting the sight. For starters try these settings: seven, eight, 10, 19, 22, and 31.

Unless your short sight is good you may struggle to see the graduations well enough, a situation which will be even more difficult when we come to set the sight to a half or a quarter minute. Most experienced shooters carry a small magnifying class in their kit, which helps out no end in this respect. Go through that exercise again.

Now when you can do this proficiently you are well on the way to being able to do all you need to do to set your sights to a predetermined setting.

Setting to fractions

Setting them to a half or a quarter is only one stage further from what we have just covered so let's crack on while it's fresh in the memory and start in the same manner.

Suppose we want to set our sights at 6½. The zero line will be between five and 10 (because six is between five and 10). What comes next may sound dreadfully complex but it isn't really. Since we are not dealing with a whole number, no line on the vernier will line up with the elevation scale; but 6½ is a bit more than six and a bit less than seven. The first and second lines on the vernier will both come close to lining up but won't quite make it, the other two will be nowhere near. The sight will look like figure 3 (below). Look at this closely and you will see the first line on the vernier (six) and the second (seven) are equidistant between 10 and 15 on the elevation scale. Put another way the sight setting is exactly half way between six and seven, which is 6½!

Obviously this principle applies to any setting that ends in ½. Now there is only one further step, and that is setting the sights to a quarter or three quarters. This is an extension of what we have just covered. If we want 6¼ on the sights the setting will be between six and seven but will be closer to six than seven. In fact the gap between line one on the vernier and 10 on the elevation scale will be half the size of the gap between line two and 15. Conversely 6¾ will make the gap between line one and 10 twice the size of the gap between line two and 15 as in figure 4.

After this you should be able to set your sights to any elevation setting they are capable of being set to and reading off the sight what that setting is. We have, up this point, concentrated on the elevation scale because it is a little easier to read than the windage scale but the principles are the same, however the scales are duplicated, for right and left.

At this point in a coaching course one would pass round a rearsight with a setting on it and get the candidates to read those settings and also get them to apply a setting to the sight. To try to simulate that, look at the pictures of sights here. Study them closely and see if you can read them. To avoid any temptation to cheat I'll give you the answers next month.

TARGET RIFLE BASICS: READING THE VERNIER

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TARGET RIFLE BASICS: READING THE VERNIER

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