Sniping in France: With notes on the scientific training of scouts, observers, and snipers

by H. Hesketh-Prichard

Note:—The bolt lever must not be raised and drawn back when the sight is in No. 4 position, as if this is done the battle sight is sheared off.

Diagram showing 4 Positions of Backlight.

N^o 1.

ELEVATION

The elevation is obtained by raising a slide on the leaf. This slide carries the aperture, and, when set, is held in position by a spring-catch adjustment on the right of the leaf. The leaf is graduated from 200 to 1100 yards in hundreds of yards, and from 1100 to 1650 yards in fifties. The reading line is situated in the centre of the slide, and care must be taken to point out this fact clearly, otherwise men are apt to take readings from the top or bottom of the slide.

FINE ADJUSTMENT

The sight is fitted with a fine adjustment in the form of a worm screw with a milled head. By rotating the milled head clockwise we raise the elevation, and by turning it anti-clockwise we lower it. The top of the milled head is marked off into three divisions, each of which is equivalent to one minute of angle, which is about 1″ per 100 yards of the range. Thus at 100 yards it would equal 1″ rise, or fall, on the target; at 200 yards 2″; at 300 yards 3″, and so on. A reading line is marked on the top of the sight leaf to enable these minute adjustments to be made. (See [diagram].)

The advantage of a fine adjustment screw on this principle lies in the fact that, without alteration of foresight, the rifle can be zeroed with exactness in a vertical sense, for any individual hold, thus: If a man, when zeroing his rifle at 100 yards’ range, finds the point of mean impact to be 3 inches low, or high, he has only to remember that he must first reproduce on his backsight the range for which he is firing, and then add, or subtract, 3 minutes of elevation, i.e., by giving the milled head one complete turn or revolution in the required direction; he will then have his correct zero for that particular range. (Note:—Before starting to zero at 100 yards, he must raise the sight to 200 yards, and then take off 3 minutes; this is equivalent to setting his sight to 100 yards (which is not marked). With the sight so set, the “point of mean impact” should be 1½ inches to 2 inches above the point of aim.)

In addition the fine adjustment can be used to overcome the difficulty of not having the sight calibrated to read to fifties at the closer ranges. By memorizing the following table, the sniper will have no difficulty in adjusting his sight to 250, 350, 450 yards, and so on: