If you are shooting a converted Enfield P’14 or No.4, your range scale will be gradated for .303 and not the 7.62 mm you are shooting!
However he has learned from his lessons in 1958 and keeps a careful record of his actual elevations. From this knows that his elevations for RG ammunition are close to these figures but for ‘Red Box Norma’ he is able to calculate that his rise for from 300 to 500 is actually seven minutes, from 500 to 600 four and a quarter, from 600 to 900 eighteen and from 900 to 1,000 seven and a half. So, his normal elevations for this ammunition are 7, 11¼, 29½ and 37 respectively.
Now Jack has done everything as he should - with one exception. He has failed to recognise why Miss Parker* thoughtfully graduated his old No.4 sight so it read not zero but 5 minutes at 200 yards. He finds that out when he travels to Horsford to shoot in the Gresham’s School Open and finds himself shooting at 200 yards. His sight setting looks like the photograph below.
From the 1948 Parker Hale catalogue – that P14 sight range-scale is graduated for the
Mk.VII 303
Even if your rearsight was intended for use on a 7.62 mm rifle, the chances are it was graduated for British NATO spec. 144 grain ammunition, not the 155 grain Palma Match ammunition you are likely to be shooting now. Your barrel length may be different from that intended (altering the ballistics of the ammunition anyway) and maybe your sight-base.
Other than his reliance on the range-scale, Jack’s procedure was basically sound. Let’s fast forward thirty years to March 1988. Jack’s older and wiser now and he has just bought a new Swing Target Rifle with a Higginbottom rearsight. This has no range- scale. Two hundred yards has become moribund as far as most TR shooters are concerned. Jack takes his rifle onto the range and ‘zeros’ it at 300 yards, centring his group on the bull and setting the elevation scale to read zero.
Consulting his AJ Parker elevation chart, Jack now knows his elevation settings at 500, 600 900 and 1000 yards are 6½, 10½, 26½ and 34 MOA respectively.
Whether you can read it or not, it is never desirable to ever be in a position where you end up with a negative setting on your rearsight. Conventional wisdom says that you find a 100 yard range, shoot a group, centre it and set the sights to zero, or even better still wait until you go to Bisley and use their zero range. (We will deal with the zero range later) There are a number of issues with this.
For a lot of shooters, range time is precious. Even if the range has a 100 yard facility, it may not be possible to accommodate your desire to shoot at 100 yards when everyone else has a three-range competition to shoot.
There is a possibility that the bullet has not particularly stabilised at this distance and the distance between line of sight and the centreline of the bore has a more significant effect in producing a false zero. Some of these problems may be more imaginary than real.
In terms of ‘elevation zero’ we do not need
Can you read the elevation setting?
to be absolutely precise because a number of factors, - for example ammunition batch, ambient
temperature, atmospheric pressure, humidity, up
hill and down hill shooting and lighting conditions will all conspire to cause variation in zero. When we come to wind zero, however we do need to get it absolutely right.
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