Plate 21.—Types of loopholes.
2. The marksman holds his rifle in a line connecting the right shoulder, the eye and the object, hence most of the body lies to the left of the rifle. The loophole should be made to the
right, with a niche in the wall of the parapet from the hip to the armpit, to bring the left shoulder well forward. It will be found that this permits the right elbow to be placed on the edge of the parapet.
Plate 22.—Methods of constructing loopholes with sandbags.
3. Box loopholes with screens or blindage may be used, but should be placed by a skilled marksman. The great disadvantage is that the enemy notes these parapet alterations. Steel loophole plates are now provided for this type of loophole, As the Germans sometimes use a steel bullet with great penetrating power, it is advisable to place two plates together to insure protection.
4. With every precaution that may be taken it is difficult to conceal a loophole. A good plan is to deceive the enemy by using painted sandbags and preparing plenty of dummy loopholes.
5. The minimum width of loopholes should be 2-1/2 inches. If narrower than this, it is impossible to use both eyes to judge distances correctly.
6. The parapet should be so sloped that there is a maximum grazing fire when the rifle is fired as it lies on the parapet.
To insure that the bullet will not graze the parapet, although the sights are clear, look through the barrel with the bolt removed.